LI material _Ref-2010_ (1)

LOCO INSPECTORS COURSE MATERIAL For example, if the variation in super elevation between POM and wheel base is 12 mm and the wheel base is 4.57 meters, the cant gradient is 12 in 4570 or 1 in 380 Broad Gauge Para 418. Compensation for curvature on gradient:- Compensation for curvature should be given in all cases Group Minimum where the existing gradient when added to the curve A 40R00admieutsers compensation exceeds the ruling gradient. A vertical B curve has to be provided at the junction of two different 3000 meters grades when the algebraic difference between the grades C, D & E 2500 meters is equal to or more than 4 mm per meter or 0.4 percent. This curve shall have a minimum radius of 4000 meters. In this case also, the longitudinal level has to be measured to ascertain the availability of curvature. POINT OF MOUNT When a vehicle derails, the most common occurrence is the climbing of the flange of any one of the wheels of the vehicle over the upper edge of the gauge face of the rail, travelling on the rail table and then derailing. The point where the flange climbs the rail table is called the ―Point of Mount.‖ (POM). This point is the most important reference point in the accident investigation and is considered as ―O‖ station for all other further recording of track parameters. The location of POM is identified with reference to a fixed structure. The locations in rear of the ―O‖ station are identified as station number -1, -2 and so on. Similarly, the locations ahead of the ―O‖ station are identified as station number +1, +2 and so on. Sometimes, the point of mount may not be visible, but the wheel travel mark will be available on the rail table ending at the point of drop. This may be due to the lightness of the vehicle. This may also be the result of the wheel having mounted straightaway on the rail table instead of slow climbing, which could have caused the mark on the rail table, without leaving a mark on the edge between the gauge face and rail table. POINT OF DROP This is the location where the wheel of the derailed vehicle drops from the rail table first. Usually, the point of drop of both wheels of the same axle will be found opposite to each other. But in the event of only one wheel of an axle derailing and the other wheel remaining on the track, there will be only one point of drop where the wheel had dropped first, and the travel mark also will be only on one side, until both wheels derail. Grazing marks on the gauge face of the rail should not be confused with point of drop. For the purpose of investigation, the spot where the wheel had dropped from the rails can only be considered as point of drop. The distance between the point of mount and point of drop will give a fair indication of the nature of derailment, i-e, whether the derailment was due to sudden and excessive lateral force, or due to gradual reduction in the wheel load.The flange marks are important pieces of 93

LOCO INSPECTORS COURSE MATERIAL evidence which give an indication of what to look for, in the P.Way and rolling stock to pin point the cause of the derailment. 94

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LOCO INSPECTORS COURSE MATERIAL 1. Gather the staff required for restoration as well as investigation. 2. Proceed by the quickest means. If the ARME or ART is moved from your station, ensure that they are started within the permissible allowance of time. 3. Walk across the site making a general survey & looking for clues such as broken parts, wheel travel marks, shifting of track etc.. Broken components lying in the vicinity should be indicated with reference to the point of mount/drop. 4. Do not touch any component which is suspected to have been meddled with by miscreants, till permission is given by higher-ups. 5. Record joint observations of the important clues and tell-tale marks on P.Way as well as rolling stock. 6. In case of collisions, passing signals at danger etc check the brake power on the stock immediately on reaching the spot. 7. In case of defects in signalling gear, check the position of the levers in the panel and jointly record the same. 8. In case the track is shifted laterally at the location of POM, measure the gap between sleepers and ballast immediately. 9. Check the unaffected rolling stock ahead of the derailed stock for marks in the bogie trucks, foot board, trough floor etc. 10. Never permit the movement of the unaffected formation without recording all the observations about marks on the unaffected stock. 97

LOCO INSPECTORS COURSE MATERIAL 11. Try to identify the first derailed vehicle by following the wheel travel marks and intensity of damages to the running gear and under gear of the vehicles. 12. Prepare a neat sketch of the site, indicating the positions of the derailed stock, wheel travel marks, broken components, point of mount, point of drop etc. Indicate the direction of movement of the train. 13. Record the track parameters jointly. 14. Cross check the details recorded and arrange to obtain the signatures of other department supervisors before leaving the site. 15. Arrange to take photographs of important evidence such as broken components, shifting of track etc. While taking photographs, the component and location should be identified suitably, by marking with chalk or paint. 16. Arrange to take video graph of the entire site, covering the track and rolling stock including tell-tale marks on the unaffected rolling stock. Video graph should be accompanied by audio description of the component, location etc of the subject being video graphed. Usually, the responsibility for arranging photographs/ video graphs will be vested with safety counselors. It does not prevent individual branches from making their own arrangements for photo/video. 17. Safety counselor (Loco) or in his absence the SLI will arrange to remove the event recorder / speedometer chart from the loco and arrange to read and take print outs of the same. 18. Keep record of the chronology of events from the time of departure from your station, till the restoration of through traffic. This will include time of re- railment or grounding of each vehicle. TELL-TALE MARKS 1. Grazing marks on the outer rim of the derailed wheel indicates that the wheel had derailed inside the track. These marks may be seen on the vehicles preceding the derailed vehicles also. This is because the gauge widens progressively before becoming wide enough to permit derailment. 2. A vehicle which derails inside will leave travel marks on the sleepers, inside the rails. The vehicle may subsequently mount the rail where the gauge is good and travel on the rail table for a short distance before derailing outside. In such case, the point of drop which precedes the point of mount has to be reckoned as ―0‖ station. 3. The first derailed vehicle has to be identified by following the wheel travel marks and also the extent of damage to the wheel flange. 4. In marshalling yards, vehicles may derail due to side collision of the loose/fly shunted vehicles. In such cases, there may not be any point of mount. The derailed vehicle will bear hit marks on the side panels. 98

LOCO INSPECTORS COURSE MATERIAL 5. Vehicles derailed in buckled/distorted track will have hit marks on the foot boards, axle boxes, trough floor, air/vacuum pipes etc. Such marks can be seen in the vehicles preceding the first derailed vehicle also. 6. In derailments due to buckling, the track shifts laterally at the point of mount or before the point of mount. This should not be confused with the disturbance to track caused by the derailed wheels, ahead of the point of drop. 7. When loaded vehicles derail, there may be two parallel travel marks on the sleeper. One will be wider and indicates the flange mark, whereas the other will be thin and indicates the tread corner. 8. Disturbance to ballast, dragging marks on the sleepers and ballast, presence of small metallic particles before the point of mount etc., indicate the dropping of under slung components or consignment on the track or entanglement of any other object under the wheels, leading to derailment. 9. In case of rail fractures, weld failures and breakage of tongue rails, note the nature of the breakage, old or new. 10. In case of derailments over locally operated points, note whether the point is secured with cotter. If the cotter is provided before derailment, the cotter will get jammed inside the cotter hole of the locking pin after the point is split open. 11. Observe whether the stretcher bar is bent. This will indicate that the points were properly set, but forced open by the wheels. 99

LOCO INSPECTORS COURSE MATERIAL TRACK PARAMETERS TO BE RECORDED AT THE SITE 1. Reference point for starting the track measurements: Point of mount is taken as ‗0‘ Station and the track readings are taken with reference to this location. In case POM is not available, the point of drop is taken as ‗0‘ station. 2. Distance limits for taking the readings: The readings shall be take for a distance of 90 metres in rear of the POM and 45 metres ahead of the POM. The readings shall be taken at every sleeper for the first 9 metres behind POM and at every 3 metres subsequently. (P.Way manual stipulates recording at every 3 metres or every individual sleeper.) 100

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LOCO INSPECTORS COURSE MATERIAL CROSS LEVELS Just like the gauge parameter, a uniform defect in cross levels but within practical limits does not have any adverse effect on safety, stability or comfort. Here again, what are the practical limits for safety are not known. The tolerances which have been laid down from time to time for this parameter are for good riding and are not safety tolerances. This parameter too, therefore has to be discussed in general terms. 1. Cross level is the difference in the levels of the tables of the two rails of the track. 2. This is measured with the ―Gauge- cum- level‖ instrument along with ―spirit level‖. The instrument has graduated ramps at the middle. In between the two ramps, a level portion is provided where the spirit level can be placed. 3. The ramps are graduated in 2 mm divisions gauge. One ramp is graduated up to 30 mm and the other up to 200 mm. 4. The spirit level is a glass tube mounted on a frame. The tube is filled with spirit with a small air space and sealed air-tight at both ends. The trapped air causes a bubble inside the tube. 5. Cross level is measured at the same locations where gauge is measured. The spirit level is placed at the centre (level portion) of the instrument. 105

LOCO INSPECTORS COURSE MATERIAL 6. If the bubble in the spirit level is at centre, the level is correct. If the bubble moves to the left side, the left rail is high and vice-versa. 7. The bubble is brought to the centre by moving the spirit level on the opposite ramp. The graduation at the edge of the spirit level indicates the difference in levels of the rails. 8. The levels are indicated as left low or right low or correct (LL, RL,and C) as the case may be. If the spirit level is on the right-hand side ramp, the level is right low. If the spirit level is on the left hand side ramp, the level is left low. If it is in the middle, the level is correct. 106

LOCO INSPECTORS COURSE MATERIAL 9. The cross level is also take on the simultaneously, while recording the gauge 10. The cross level has to be taken under load also. Under-load reading should be taken with a loco or coach or loaded wagon. 11. The difference in the readings taken in free (floating) condition and under load gives the extent to which the track is yielding under load. Forexample, if the level in free condition is 5LL and under load 10 LL, it indicates that the LH rail is yielding under load due to improper packing / void under the sleeper. If the level under free condition is 10 LL and under load is 4 LL, it indicates that the packing under RH rail is insufficient. 12. Strictly speaking, under load reading should be taken by applying the instrument between the two bogie trucks of the vehicle. However, due to practical difficulties, the instrument is applied as near to the extreme wheel as possible. 13. In curves, the outer rail is kept at a higher level than the inner rail, to provide the super elevation. Hence there will be always a difference in cross levels. This difference is generally indicated as SE instead of LL, RL etc. 14. The variation in cross levels is a potential cause for derailment in the case of 4- wheeled empty wagons. When the variation in cross level is beyond the deflecting capacity of the primary suspension of the vehicle, the primary suspension will fail to perform its duty of guiding the wheel downward to match the track irregularities. 107

LOCO INSPECTORS COURSE MATERIAL PRECAUTIONS TO BE OBSERVED WHILE TAKING CROSS LEVELS  The gauge for measuring cross level is graduated in 2 mm divisions.  IRPWM stipulates that the cross levels should be measured to 2 mm accuracy.  When the edge of the spirit level is in between two graduations, it can be interpreted to the lesser of the two graduations.  However, should it be decided to interpret it to the higher of the two values, the same convention should be observed for the entire reading. In the diagram above, the edge of the spirit level is between 46 mm and 48 mm. normally it is taken as 46. But if it is taken as 48 mm, the same convention should be followed throughout. During routine maintenance, the P.Way supervisor checks the twist on a predetermined cord length, generally 3.6 metres. However, for the purpose of calculating the twist during accidents, the variation between cross level at the point of mount which is the location of leading wheel of the wagon / bogie and the cross level at the rigid wheel base distance which is the location of the trailing wheel of the wagon / bogie is calculated first. When the cross levels at both the above locations are on the same rail i.e. RL/RL or LL/LL, the difference between the two values is found by subtracting one value from the other. If the cross levels at the leading wheel location and the trailing wheel location are on opposite rails i.e. LL/RL, the difference between the two values is the sum total of the two values. Example: Cross level at POM ………………………………… 5 LL Cross level at rigid wheel base distance…………… 11 LL Cross level variation between the two wheels…… 6 mm Cross level at POM ……………………………… 5 LL Cross level at rigid wheel base distance………… 5 RL Cross level variation between the two wheels…… 1 108

LOCO INSPECTORS COURSE MATERIAL MEASURING THE VERSINE When a cord is stretched across the two points on the periphery of the circle, the vertical distance between the mid-point of the cord and the arc of the circle is called the versine. Versine is measured to check the uniformity or smoothness of a curve. Abrupt changes in curvature result in sudden increase in angle of attack of the leading outer wheel and increase the friction between flange and rail. On curves other than points and crossings, turn-outs and turn-ins, the versine is measured with a 20 metre nylon chord at 10 metre intervals. For this, the locations are marked with POM as ‗0‘ station and other stations at every 10 metres for 90 metres in rear of point of mount and 45 metres ahead. However, if the portion ahead is badly disturbed, only one station can be marked ahead of POM. The equipment for measuring versine consists of two specially designed forks, a specially calibrated scale and a spool with nylon cord of about 30 met There is a slot in the fork for passing the nylon cord through. This slot is 25 mm away from the bottom wing of the fork which contacts the gauge face of the rail. After marking the stations, one fork is held at +1 station and the other at -1 station the upper wing of the fork is placed on the rail and the lower wing is allowed to bear against the gauge face of the rail. The nylon cord is inserted in the grooves of the two forks and held tightly by hand. At the mid-point (―0‖ station‖), a scale mounted with handle is held under the cord against the gauge face. The reading is then directly measured by using the special scale, in which the Zero marking is 25 mm away from the edge. This is because the groove in which the cord is held is 25 mm away from the gauge face. 109

LOCO INSPECTORS COURSE MATERIAL  On the gauge face of the outer rail  Taken with 20 m Chord  Stations marked 10 m Apart  Versine recorded at every 10 m for 90 metres in rear & 45 metres ahead Station No. Versine +4 79 +3 88 +2 71 +1 92 0 99 -1 80 -2 88 -3 78 -4 94 -5 101 -6 79 -7 81 -8 82 -9 90 110

LOCO INSPECTORS COURSE MATERIAL The versine for a curve is given by the formula: V = 125. C² / R where V is the versine in mm, C the length of cord in metres and R the radius of curve in meters. For curve of 1° or 1750 metres radius, the versine on a 20 metre cord will be:125x20x20/1750=28.57mm, rounded off to 29 mm.For 2° it will be 58mm, for 3° it will be 87 mm and so on. Tabulating the versine Station Versine in Variation Remarks mm Stn to Stn +1 Stn In Disturbed Portion 0 89 -1 76 13 One end of chord in transition portion -2 94 18 Transition -3 80 14 Transition -4 4 Transition -5 76 21 -6 27 97 -7 70 8 -8 10 -9 62 8 52 44 111

LOCO INSPECTORS COURSE MATERIAL  AVERAGE VERSINE OF CIRCULAR PORTION = (89+76+94+80+76+97)÷6 =85.33MM  25% OF AVERAGE VERSINE OF CIRCULAR PORTION = 21.33 MM IRPWM Para 401 (3). For measuring versine of a curve, 20 metres overlapping chords should normally be used with stations at 10metres intervals. For checking radius of turn-out and turn-in curves, overlapping chord of 6 metres should be used and the versine measuring should be located at every 1.5 metres. Para 421 (3) (a) the running over a curve depends not only on the difference between the actual versine and the designed versine but also on the station-to-station variation of the actual versine values. This is because; it is the station to station variation of versine, which determines the rate of change of lateral oscillation on which the riding comfort depends. The limit for station to station versine variation for 3 speed group viz. 120 km/h and above, 120 km/h and up to 80 km/h and below 80 km/h and up to 50 km/h should be considered as below: RANGE LIMITS OF STATION TO STATION 120 km/h and above Below 120 km/h and up to 80 km/h VARIATION Below 80 km/h and up to 50 km/h 10 mm or 25% of the average versine on circular curve, whichever is more. 15 mm or 25% of the average versine on circular curve, whichever is more. 40 mm or 25% of the average versine on circular curve, whichever is more. CREEP Creep is the longitudinal movement of track, caused by various factors. The creep is caused by the ironing out of yielding track, by the moving load and its impact on the ends of the rails, especially at times when they are in the process of expansion or contraction due to temperature variations. Some causes of creep are given below:-  Rails not secured properly to the sleeper.  Insufficient ballast which yields to the movement of sleeper during wheel movement.  Badly maintained rail joints.  Rails lighter than the prescribed type for the particular section of track.  Improper expansion gap.  Decay of sleepers.  Uneven spacing of sleepers.  Improper drainage.  Loose and uneven packing. 112

LOCO INSPECTORS COURSE MATERIAL  Rail seat worn out in the metal sleepers. Creep in the track causes the sleepers to go out of square, distorts the gauge, causes shearing and breaking of spikes, bolts and fishplates and in some extreme cases buckling of the track. MEASUREMENT OF CREEP:- At accident site, the creep has to be measured at the nearest kilometer. For this purpose creep posts are erected at approximately one km intervals, opposite to the fish plate joints. The creep posts are discarded rails fixed vertically on either side of the ballast cushions. The centre line is marked with chisel on the top of the rail in line with the rail joint. These posts are so erected that they are slightly above the rail level. A nylon cord is held over the two posts on the centre line marked in the post. The displacement of the rail joints with reference to this cord is then recorded separately for the left rail and right rail. If the joint had moved forward with reference to the direction in which the measurement is being taken the creep is indicated as positive. If the creep is opposite to the direction of the measurement it is indicated as negative. Para 242 (6) of IRPWM reads as under:- Permissible amount of creep: - Creep in excess of 150 mm shall not be permitted. Whenever creep is noticed, it is necessary to check the availability of gaps in fish plate joints from POM up to the next creep post. This is called gap survey. Buckling Buckling of track occurs when high compressive forces are created in the rails associated with inadequacy of lateral resistance in the track at the place. How to identify buckling:  Point of mount will be found at the distorted location or slightly ahead of the distorted location;  More than one travel mark can be noticed from the POM.  Gap can be noticed between the edges of the sleepers and the ballast on one side and heaping of ballast on the other side;  Record the extent of displacement of the track with reference to ballast and the original alignment immediately before the conditions are disturbed; 113

LOCO INSPECTORS COURSE MATERIAL  In case of LWR/ CWR, measure the gap at the nearest expansion joint;  Breathing Length is that length at each end of LWR/CWR, which is subjected to expansion/contraction on account of temperature variations.  Switch Expansion Joint (SEJ) is an expansion joint installed at each end of LWR/CWR to permit expansion/contraction of the adjoining breathing lengths due to temperature variations. ANNEXURE V (Para 5.6) Gap at SEJ for various rail temperatures and track structures, Initial gap is to be provided at distressing temperature. Gaps at SEJ shall be adjusted at the time of laying/subsequent distressing of LWR/CWR, shall be as under: Rail Section Gap at ‗td‘(mm) 60 kg (UIC) / 52 kg 40mm Others 60mm The gaps between the reference mark and tongue rail tip/stock rail corner at various rail temperatures shall not differ by more than ± 10 mm from the theoretical range.Where fish plated or SWR track is joined on one side of SEJ, the gap between the reference mark and 114

18 19 Weight 52 Kg / 90R / Rails 9 10 11 12 Left Width of shoulders in cm. 12 Sl. No. LOCO INSPECTORS COURSE MATERIAL 75 R etc. from outside of Rail 20 Rail fastenings Right 3 Type e.g :- sandy, tongue rail tip/ stock rail corner on LWR/CWR side shall not differ by more than ± 10mm Condition of wear Dog / screw spikes, loamy, clay, from half the theoretical range. 21 (attach rail profile if keys, tie bars, cotters, 13 Left 45 Moorum, wear is heavy) Black cotton, etc. I. ANNEXURE 7 / 2 TO IRPWM 1986 PART –A loose jaws etc. Right Number per sleeper Condition - firm, Proforma showing the detailed particulars to be collected in the case of Permanent Way 115 seat. Type – wet, slushy, etc. during an accident:- wooden, CST.9, 22 23 Condition Tight or 14 steel trough, etc. Type Soil Ballast loose Codition - new, of formation 15 16 second hand, 6 Condition Hogged, Rail joints. damaged, Sleepers Rain fall battered, low etc. unseviceable, etc. 7 Type- stone, Staggered or square Moorum, Sand, 24 Density Ash, etc. Creep- Direction and extent of creep, type of 17 Square or not Depth below sleeper creep anchors used bottom in ms. with numbers per rail Packing, Stating whether clean in the affected section. loose or sound or caked. 8 Drainage

89 Examination of alignment for 12 Station No. 25 General remarks about perceptible kinds of track cracks or fracture of 10 distortion in the vicinity of the 34 Distance apart in Note:- Left and right are with respect to direction of Train movement. 26 27 28 29 fish- plates, fish bolts and point of derailment. Versine in mm. metres other components. 116 Cross level (mm)Cross level (mm)  The data in Col.2 to 25 need not be collected when the defect is obviously Location of Subsidence of track. Gauge slack or and indisputably on account of sabotage and / or obstruction on track. Description of anti- point of mount 11 tight from the sabotage measures like LOCO INSPECTORS COURSE MATERIAL On 20 M or 10 M chord exact (mm)  Only broken track material which is not indisputably to be broken after the reverse jaws, welded depending on practice 5 accident should be included in Col.25 and should be preserved. rails, etc. prevalent on the Railway for Under no 12 flat curves more than 600 M load condition  Col.26 need be filled in, only when there is suspicion about the sabotage Whether on Location of radius. being the cause of the derailment. straight, curve or point of derailment. 67 Under load 30 transition. On 10 M or such shorter condition to  Sag extends 90 metres on either side of theoretical junction of grade lines chords as considered be measured (Col.28 and Col.30). Whether on a necessary for sharp curves with a II. ANNEXURE 7 / 2 (Contd) PART - B falling grade, level (less than 600 M radius on locomotive / Track measurements or rising grade and B.G. and M.G.) fully loaded or on sag. wagon / Remarks regarding length of coaching Whether on transition, degree of curve and stock bogie. straight, curve or specified super-elevation general transition. alignment etc. Marks on sleepers or rail top. Whether on a Longitudinal level to be recorded falling grade, level in the case of M.G. and N.G. in Grinding or or rising grade and case of sags and curves. rubbing marks on or on sag. rails. 13

LOCO INSPECTORS COURSE MATERIAL Note :- 1. The point of mount should be marked station no. '0' and stations Numbered serially as (+) for measurements ahead of site of derailment and (-) for measurements in rear. 2. The cross level will be measured on the left rail only as determined from the direction of movement. 3. Normally measurement will be taken at station 3 M apart for a distance of 45 metres either side of 0 station if the cause of derailment is indisputably known, otherwise they will be taken for a distance of 90 metres in rear and 45 metres ahead of '0' station. 4. Where necessary, measurements for Col. 3, 4 and 5 may, in addition be taken at individual sleepers. 5. This pro forma need not be filled when the cause of derailment is obviously established as due to sabotage, obstruction on track, broken axle, and / or spring having fallen off prior to point of derailment. 6. Longitudinal levels should be recorded for 300 meters on rear and 100 metres in front, in case of straights at the middle of each rail and at Versine recording points on curves @ 20 / 10 M intervals. ***** 117

LOCO INSPECTORS COURSE MATERIAL CHAPTER V CARRIAGE &WAGON VEHICLE BODY In general, the vehicle under frame should not have excessive twist. Besides, the rectangular under frame should not be distorted into a parallelogram. We may now discuss the various rolling stock defects, analyzing their effect on derailment proneness. First, the general defects which are more or less common to the various types of rolling stock, will be dealt with. The defects particular to each type of rolling stock will then be taken up. Bogie: Hindrance to bogie rotation is an important aspect to be looked for in Case of derailments involving Bogies etc. Brake gear: Deficiencies in brake block and components. Twist under frames: To determine any angular running of wheel sets. Buffer: Either deficient or dead or displaced. Dimensional tolerances are available to determine the above features. Apart from the above, different rolling stock viz. engines, coaches and wagons have other characteristics/ tolerances laid down for their components and it would be necessary to have an in-depth study of these components at the accident site. Vehicle Oscillations A vehicle while travelling over track, does not move smoothly, but due to various reasons, executes a variety of oscillations. Considering the 3 axes  X axis: along the track  Y axis: lateral to the track  Z axis: vertical direction And that there are 2 modes pertaining to each axis via, linear and rotational, there are in all 6 modes of oscillation, 118

LOCO INSPECTORS COURSE MATERIAL The six modes of oscillation. Axis Motion Type  Linear Rotational  X Shuttling Rolling  Y Lurching Pitching  Z Bouncing Nosing (also called ‗yaw‘) The combined oscillation of rolling and nosing when violent is called hunting. Cause-wise, there are two broad categories of oscillations: 1. Self excited: these are due to wheel Conicity. 2. Other than self excited: These are due to  Track irregularities  Varying elastic characteristics of track  Suspension Characteristics of the vehicle  Disposition of load on the vehicle  Vehicle operation features In every situation, the wheel carry a certain quantum of vertical load, which may vary from time to time based on the vertical alignment of the track. There is a certain quantum of lateral forces exerted by the wheel flange on the rail. The ratio of lateral flange force to the vertical wheel load has a great significance in the derailing tendencies of a vehicle. This is usually expressed as Y/Q ratio, where Y is the lateral flange force and Q the vertical wheel load. Early studies and research have concluded that Y/Q= (tan β - µ)/1+µ tan β where β is the flange angle and µ the coefficient of friction between rail and flange. From the aforesaid formula, the lateral force Y can be calculated based on the static load on each wheel of the vehicle. When Y/Q is less than 1, the vertical load is capable of overcoming the lateral force. When the ratio is above 1, the conditions favourable for flange climbing. The most likely cause of a flange climbing derailment can be found out only by examining the suspensions of the vehicle, the wheel profiles, and the distribution of the pay load on the wheels and the parameters of the track. EFFECTIVE CONICITY OF THE WHEEL TREAD With wear, the effective Conicity increases, this has adverse effect on critical speed of the vehicle and running stability. The tread is given a taper of 1 in 20. Therefore, the diameter measured at the outer edge of the tread will be approximately 10 mm less than the diameter at the corner between flange and tread.  Dia at R…. D ‗say‘  Dia at P……. D – (65¸20)x 2 or D – 6.5  Dia at Q…… D + (31¸20)x 2 or D + 3.1 For a new wheel,  Thickness of flange at S… 28.5  Thickness of flange at Q… 28.5 +(28-13) ¸2.5 = 34.5 A conical body, when rotated on a surface, tends to rotate around its smaller diameter. The wheel tread has the same tendency due to the conicity. Because of this, the left wheel tread tries to pull towards the left and the right wheels tread to the right. 119

LOCO INSPECTORS COURSE MATERIAL As a result, there is continuous tendency for the wheel to move from left to right and vice- versa. The path described by the wheel tread on the rail table will be as follows: As a result of this wavy motion of the wheel tread, which is known as sinusoidal motion, there is a continuous flange thrust alternately on any one of the two rail faces, even on a straight track. Thus, the wheel flange is always having a small positive angle of attack either on the right rail or left rail. While on a curve, the wheel on the outer rail develops a positive angle of attack, since the wheel initially tries to follow the body of the vehicle. The effect of the positive angle of attack is to create a friction between the flange and the rail. The wheel negotiates the curve by the outer wheel attacking the outer rail and then sliding to take a radial position with reference to the curve. This is a continuous process till the wheel passes through the entire length of the curve. Due to the spring characteristics of the vehicle and due to the characteristics of the track geometry, the vehicle develops oscillations along the longitudinal, lateral and vertical axis of the vehicle. 120

LOCO INSPECTORS COURSE MATERIAL The upward bounce about the vertical axis, rolling about the longitudinal axis and pitching about the lateral axis induce changes in the instantaneous wheel load on any or all of the wheels from time to time. The lurching along the lateral axis and nosing about the vertical axis create lateral forces. Shuttling along the longitudinal axis adds to the effect of traction and braking shocks. One can observe from the figure shown below that the bouncing in vertical axis (difference in height of the vehicle body on the springs) One can observe from the figure shown above that the nosing in vertical axis (difference in leaning of vehicle body on track i.e. left to right vice versa) 121

LOCO INSPECTORS COURSE MATERIAL One can observe from the figure shown below that the Rolling about longitudinal axis (difference in leaning of vehicle body on springs i.e. left to right vice versa) One can observe from the figure shown below that shuttling about longitudinal axis (difference in moving of vehicle body on track i.e. to-and-fro vice versa) One can observe from the figure shown below that lurching about lateral axis (difference in moving of vehicle body on track i.e. left to right vice versa) One can observe from the figure shown below that pitching about lateral axis (difference in moving of vehicle body on track i.e. up down vice versa) 122

LOCO INSPECTORS COURSE MATERIAL BUFFERS Buffer defects have significant effect on derailment- proneness. The effect basically is due to eccentricity of buffing forces caused by such defects. The eccentricity in buffing forces can be in: Vertical direction, in which case Q values are affected horizontal direction, when Y values are affected inclined direction, when both Y and Q values are affected. Maximum and minimum permissible buffer heights in Broad Gauge (goods and coaching) are shown below: EMPTY : 1105mm LOAD : 1030mm i) Difference in heights of buffers of adjoining vehicles. This can happen at the junction of a set of empties and a set of loaded wagons (Fig.) ii) Drooping buffer iii) Buffer displaced vertically from its normal position, due to headstock being bent. (On B.G. Maximum permitted displacement of buffer face due to head stock being bent is 35 mm in any direction from its normal position in case of wagons and 38 mm in case of coaching stock; see Fig. DEFECTS RESULTING IN HORIZONTAL ECCENTRICITY OF BUFFING FORCES  Buffer deficient  Dead buffer A buffer shall be considered dead when it is ineffective or when its projection from the headstock (on B.G.) is below the prescribed minimum limits viz. a) Goods stock: For long case: 584 mm For short case: 406 mm (maximum limits are 635mm and 456 mm respectively.) b) Coaching stock: 584 mm (maximum limit is 635 mm) N.B. On wagons, not more than one dead buffer s permitted on two consecutive wagons on a train. However, no dead buffer is permitted for coaching stock. 123

LOCO INSPECTORS COURSE MATERIAL DEFECTS RESULTING IN ECCENTRICITY OF BUFFING FORCES IN BOTH DIRECTIONS Buffer face is displaced from its normal position in an inclined direction, due to headstock being bent. On B.G. maximum permitted displacement of buffer face due to headstock being bent is 35 mm in any direction from its normal position in case of wagons and 38 mm in case of coaching stock. Irregular loading (B.G. stock): Difference of height from rail level of more than 64 mm between any two buffers on the same vehicle measured at the head stock. Flange of any wheel within 25 mm of the bottom of vehicle. Now we will be taking up some common types of rolling stock and discussing their additional typical features and defects in subsequent paragraphs. BUFFER HEIGHTS 1. Buffer height has to be measured at the head stock, after uncoupling the wagon and placing on a level track. The height is measured from the rail table level to the centre line of the buffer casings of the side buffers and centre line of the striker casting of the CBC. Buffer drooping is found out by measuring the height at the centre of buffer face as shown in fig. Forces develop along the length of the train, if the lines of action of the draw and buffing forces on the adjacent buffers are not on the same plane, that is, one end of the vehicle is higher than the adjacent end of the next vehicle. In other words, if the buffer heights measured at the head stocks of the adjacent vehicles are not even, the transmission of tractive force and braking force will be on different planes. During sudden braking of the train the buffer at the lower plane will tend to lift the buffer at the higher plane, causing the wheel to lift up and go over the rail table instantly. Or the vehicle may travel in lifted condition during the brake application and if the brakes are released suddenly the vehicle will float over the rail table. In goods /coaching yards, where there are sharp turn-outs, one vehicle may be following a RH/LH curve, whereas the vehicle behind that is still on a straight road. If the speed over such turn-outs is not 124

LOCO INSPECTORS COURSE MATERIAL strictly observed, the longitudinal forces will come into play to result in side-ways interlocking of buffers. This will result in generation of lateral force and cause a derailment. From practical experience, several situations can be visualized. A vehicle may be moving on a straight, plain track, or on a straight track on rising or falling gradient, or on a curved track with super elevation, a curved track with negative super elevation etc. Bogie stock Body of such stock is supported on two bogies or trolleys, each of which may comprise two- axles (i.e. four wheels) with rigid wheel-base or three axles (i.e. six wheels) with rigid wheel- base. Bogie, trolley or a truck can rotate or rotate and slide laterally as a group relative to the vehicle body and other bogie, trolley or truck. BOGIE ROTATION Hindrance to bogie rotation is an important defect to look for in event of any bogie stock being involved in a derailment. When a bogie stock derails, it should always therefore be checked to see if there is any defect that would tend to hinder free bogie rotation or cause jamming of bogie against rotation. Where to look for such defects? It will be clear that when a bogie rotates, it continues to support the vertical weight of the vehicle body. Thus, the bogie rotation takes place at those surfaces where the weight of vehicle body is supported on the bogie. Such surfaces should be checked for any tendency towards jamming or hindrance against bogie rotation. Possible defects are: Lack of lubrication (surfaces where lubrication is required e.g. surfaces of steel-to-steel contact. For instance, at phosphor bronze surface no lubrication is necessary).Ingress of dirt, coal ash etc. between the surfaces in contact. The particular locations required to be checked for some common types of rolling stock have been indicated in the respective Paragraphs. 125

LOCO INSPECTORS COURSE MATERIAL TWIST IN UNDERFRAME LONGITUDINAL TWIST  This can be detected by measuring the length of the diagonals joining the four corners of the under frame after keeping the vehicle on a level track.  A longitudinal twist would cause the axles to remain persistently angular to the track, thus increasing the derailment-proneness. VERTICAL TWIST  The vertical twist is detected by measuring the height of sole bar at the four corners of the under frame above the rail level, keeping the vehicle on a level track.  A twist in under frame is equivalent to a twist in the track and thus will increase derailment proneness of the vehicle.  A vertical twist of 20 mm can appreciably increase the derailment proneness. DIAMOND FRAME BOGIES There are three common types of bogies in this category:  Talbot bogie (used under BOBs wagon) (RDSO‘s Report No. M.208 and M. 209)  RDSO‘ Soft Ride bogie (RDSO‘s Report No.M.261)  Casnub bogie (RDSO‘s Report No. M.265)  Defects  Items and features to be checked during derailment investigation for defects in Diamond frame bogies in general: General in wheel sets, axle box assembly, bolster lug-side frame member guide surfaces, spring gear, buffing gear and brake gear Clearances at the bolster lugs slide frame member guide. Particular Surface of the centre pivot for any hindrance to bogie rotation (also check the side bearers in this context) spring loaded friction sunbbers (except in Talbot bogie) Items and features to be checked during derailment investigation for defects in 3-piece trucks in general  Defects in wheel sets, axle box assembly, bolster lug Defects in wheel sets, axle box assembly, bolster lug side frame members guide surfaces, spring gear, buffing gear and brake gear clearance at the bolster lug-side frame member guide Surface of the center pivot for any hindrance to bogie rotation (also check the side bearers in this context) Spring loaded friction snubbers.  The two side frames and the bolster-three in all are the only structural members, from which feature these bogies derive their name. Due to this arrangement these trucks suffer from an inherent disadvantage, in that the axles can become angular to the side frames in a parallelogram fashion while negotiating curves or turnouts. This phenomenon is called ‗lozenging‘ or ‗parallelogramming‖ which gives rise to high flange forces during curve negotiation (see Fig.). 126

LOCO INSPECTORS COURSE MATERIAL This aspect should therefore be kept in view during derailment investigation involving these bogies. Hence, for defects in the context of hindrance to bogie rotation, surfaces of the following should be checked, Mainly the centre pivot. Since one of the two side bearers also carries load during vehicle motion, the side bearers also should be checked for any defects or features that would tend to cause jamming or hinder free bogie rotation. The permissible variation in tread diameter of trailer and motor coach bogies at the time of tyre turning or while replacement shall be as under;  Wheels on the same axles : 0.5 mm  Wheels on the same bogie : 0.5 mm  Wheels on the two bogies : 13 mm under the same coach FIAT BOGIE FIAT bogies with LHB coach were imported from Linke of Germany along with technology transfer. The bogie is of a Euro fima type construction, consisting of Y shaped longitudinal box section beam connected by two tubular members. The bogie is of two stage suspension. The primary suspension is combined effect of nested helical springs, control arm and rubber elements. The axle guidance between axles to bogie is achieved by control arm assembly. The secondary stage suspension is a combined effect of nested flexi-coil helical spring, rubber elements and rubber bellows. The unique feature of the suspension is the fitment of anti-roll bar, which controls the rolling of the vehicle body without reducing the vertical flexibility and even stiffens the secondary suspension. The tractive and braking forces from bogie to coach body are transmitted through rocker arm assembly, which swivels around centre pivot. A rectangular shaped mounting frame connected with tubular members are housed with longitudinal and lateral rubber bumps through unique body-bogie connection above secondary suspension through which body weight is transmitted to bogie. The bogie is provided with disc brake system, tapered roller bearing and permanent earthing connections to avoid passage of current through roller bearings. It is also provided with wheel slip protection arrangement. Fig. show details of Fiat bogie. In CASNUB bogies, there is no spring in the primary suspension. The bogie side frames are connected only at the centre by the bottom spring plank. This design facilitates the four wheels on a trolley to freely follow the rail table and hence the diagonal variation in the primary suspension does not have the effect of off-loading. 127

LOCO INSPECTORS COURSE MATERIAL ROLLING STOCK SUSPENSION SYSTEMS AND DEFECTS The defects/deficiencies in the various components of rolling stock have been laid down in IRCA Rules part III & IV, schedule of dimensions and relevant instructions. An understanding of the basic functions of a suspension system and its components enables a more rational identification of defects in rolling stock.There are three distinct portions of rolling stock: • Wheel sets • Suspension system • Vehicle body SUSPENSION SYSTEM The principle of suspension system embraces two basic features: -Springs (here we mean the main bearing springs which act in the vertical direction) -Dampers Thus any defect which directly or indirectly affects the functioning of springs makes the vehicle more derailment prone through the Q parameter. The main bearing springs may be provided in a vehicle suspension: - In single stage, or - In double stage Single stage suspension In this there is only one stage of springs between the wheel set and the vehicle body. Commonest example of this is the ordinary 4 - wheeler wagon. Normally all freight stocks have single stage suspensions. Some of the diesel and electric locomotives also have single stage suspension. Double stage or Two-stage suspension In this, springs are provided in two stages between the wheel set and the vehicle body, viz. - Primary stage - Secondary stage Primary stage This comprises the set of springs which bear on the axle boxes, directly or indirectly. Such springs are called primary springs and the suspension, primary suspension. Secondary stage This comprise the set of springs which through a bolster, bear directly the weight of the vehicle body and transmit it to a bogie frame which further rests on the primary springs. Such springs are called secondary springs and the suspension, secondary suspension. Coaching stock normally has two-stage suspension. Some of the diesel and electric locomotives also have two- stage suspension. Springs commonly in use are of three types:  leaf spring or laminated spring  helical spring  air spring 128

LOCO INSPECTORS COURSE MATERIAL The camber of a spring is defined as the camber at the mid span of the eyed plate (measured at the outer surface) in reference to the ends of the plate at beginning of the eyes). When the spring is free and carrying no load, the camber, is called free camber. Under load, the spring deflects and the camber changes. Such camber which varies with load is called the working camber. The terms camber and deflection when applied to laminated spring have different meanings. Say, a laminated spring has a free camber of 75 mm. In that case, deflection is zero. If the spring is loaded so that the spring becomes flat then working camber is zero, where as the deflection is 75mm.The relevant curves, assuming straight line relationship, would be as shown in Fig. The deflection behavior of a leaf or laminated spring is determined by checking its - Free camber, and - Working camber. Free camber when measured of a new spring, should in no case be less than the design value stipulated for that particular type of spring. However, the measured free camber may be more than the design value by certain tolerance. In general, tolerances of measured free camber from design camber are: B.G Loco & carriage spring - 0 to +3 Goods stock - 0 to +6 Helical spring: A rod or wire coiled with a certain pitch, forms what is known as helical spring. When an outer coil has one or more inner concentric coils of obviously smaller diameters, it is called a nest of springs. COMMON DEFECT IN HELICAL SPRINGS  Cracked or broken spring  shifted spring  Spring fully compressed  Loss of elasticity, resulting the spring getting fully compressed in dynamic condition (this causes shocks) Spring Camber The measurement of spring camber is prescribed for 4-wheeler IRS wagons only. The load/tare camber is to be measured only after re-railing the wagon on level incanted track for measuring the free camber. The load on the spring has to be completely released by lifting the wagon body. After releasing the shackle pins from the spring eyes, the free camber is measured by stretching a string across the two eyes of the top plate. The reading shown by the scale (placed near the spring buckle) against the string gives the free camber. For load/ tare camber measurement, the body weight is not released, but the wagon is placed on a level incanted track. In all cases, it is desirable to send the spring for load deflection test to ascertain the characteristics. When springs are taken out from the rolling stock, they should be identified by marking the location from which they are taken out, such as front trolley, right leading, rear trolley right trailing etc. Coil springs Details on coil springs are not specified to be recorded in the Rly.Bd pro forma. This is because; a primary coil spring in coaching stock is permitted in service even if it is broken. 129

LOCO INSPECTORS COURSE MATERIAL As per RDSO instructions a primary coil spring in broken condition can be allowed to destination since it is found to have no impact on safety. However, if insisted by the Enquiry committee, the height under load should be recorded after placing the coach on alevel track. Free height of the spring should be measured after taking out the spring. AIR SPRING (Fig. ) This is similar to a car tyre and is permanently connected to an auxiliary surge reservoir by an interconnecting pipe. The mass of air in the system is controlled by means of a mechanical leveling valve. Any defect in the spring gear and its assembly affects the Q values (refer Nadal‘s formula). AXLE BOXES Axle boxes are basically of two types: -Plain bearing -Roller bearing Defects in plain bearing axle box Bearing brass of not correct step size to suit the journal size Bearing brass not seated uniformly on the journal or rocking or getting displaced during motion as shown in Fig. Axle box level not adjusted by correct thickness of slipper plates to suit differing thickness of bearing brasses and journal diameters Oil or packing deficient as to result in inefficient lubrication of the journal.Any of the above defects can lead to hot axle condition which further leads to persistent angular running of the axle and off-loading as explained earlier. B.G Trolley(mm) 4 wheeler(mm) Minimum 5 5 Maximum 10 10 Play of bearing at the journal Minimum and maximum permissible lateral play between the bearing brass and the journal (see Fig.) shall be as indicated below: If the play is excessive, lateral oscillations increase effecting Y& Q adversely, and angularity of the axle increases. 130

LOCO INSPECTORS COURSE MATERIAL Lateral clearance The minimum and maximum permissible total lateral clearance between the axle guard and the axle box groove or the horn cheek and the axle box with plain bearing shall be as under: - Goods and coaching stock bogie & 4-wheelers (B.G. & M.G.) Minimum Bogie& 4wheeler(mm) Box wagons(mm) Maximum 6 20 10 25 Longitudinal clearance The minimum and maximum permissible total longitudinal clearance between axle guard and the axle box groove or the horn cheek and axle box with plain bearing shall be as under: - Goods and coaching stock bogie & 4-wheelers (B.G. & M.G.) Bogie&4wheeler(mm) Box wagons(mm) Minimum 3mm 12mm Maximum 10mm 18mm As in the case of increased play at journal level, if the above mentioned clearance are exceeded, their effect on safety is the same as that of increased play between the wheel set and the track viz - Lateral oscillations will increase leading to adverse effect on Y & Q, increased angularity the axle. I Inspection of rolling stock in case of an accident Wheel and Axle face particulars (In case of breakage of wheel/axle) Axle face Ultrasonic Stamping particulars On wheel disc. Regarding particulars particulars On Manufacturing/RA/RD the hub of the disc. L1 L1 L1 L2 L2 L2 L3 L3 L3 L4 L4 L4 R1 R1 R1 R2 R2 R2 R3 R3 R3 R4 R4 R4 Wheel set Two wheels and an axle form a wheel set. A wheel set should have running stability and have safety against derailment by mounting. It should negotiate the various track features viz. Points, crossings, curve etc. safely and without damaging the track components. The rolling stock involved in accident must be inspected in the presence of nominated team of supervisors and results should be recorded in the prescribed format. The main items of inspection are as under: 131

LOCO INSPECTORS COURSE MATERIAL Wheel gauge Wheel gauge is the distance back-to-back of the on a wheel set. The wheel gauge should be checked at quarter points (Fig).Wheel gauge is the distance between inside faces of the flange on the right and left side wheels of an axle. There should be no variation in the values of wheel gauge - measured at four points 90 degrees apart on a wheel set.However the actual value of the wheel gauge can vary as per - tolerances given (Ref. IRCA Pt.III & IV, 01.05.1982) Goods B.G. SSttaoncdka(mrdm) Maximum 1600 Minimum 1602 1599 Coaching B.G. sSttoacnkd(amrdm) 1600 Maximum 1601 Minimum 1599 MEASUREMENT OF WHEEL GAUGE Wheel Gauge or Wheel Distance: The wheel gauge or the wheel distance is the distance between the inner rims of the two wheels on the same axle. Measuring of wheel distance is done applying the wheel gauge, horizontally. As per Rly.Bd. Format, ―The wheel gauge is to be measured in empty condition and at the horizontal plane passing through the center of the axle.‖ No variation whatsoever is permitted among the values of wheel gauge measured at quarter points. A variation in the values of wheel gauge measured at quarter points indicates a bent axle. A bent axle on motion will start wobbling causing severe vibrations between the bearing and the journal and consequently greater wear and friction between the two. This may cause white metal of the bearing brass to become hot and fuse out, further increasing the friction between bearing and journal. This would result in the axles, running hot at the journals. As the bearing friction at the two journals in hot axle condition cannot be expected to be the same, the end at which friction is more would be more restrained than the other and under the tractive forces the axle would turn and run persistently angular. Besides, with the white metal fused in hot axle condition off-loading of the wheel will take place. Owing to fatigue, axle could also fracture. 132

LOCO INSPECTORS COURSE MATERIAL The wheel gauge is measured at four quadrants to find out the extent of bent axle. Brackets help to keep the gauge over the flange. The gauge can be directly read from the scale attached to the gauge. A spirit level is place to ensure that the gauge is level with the horizontal. After ensuring that the track is level, the load on the wheel is released and the gauge is placed at the quadrant between the top and bottom quadrants. When applying the spirit level, it should also be ensured that the wheel contact on both rails is at the tread centre. Otherwise, the 1 in 20 slope in the tread will keep the axle at an angle with the rail table result in wrong reading of the gauge. The wheel is then rotated and the gauge taken at the next quadrant. The gauge used for measuring the wheel gauge is called ―Wheel Gauge‖. The gauge consists of one spring loaded tip and another fixed tip (Two ―L‖ shaped). The wheels are required to be gauged at three or four - quarters (as per possibility) and recorded duly indicating the following: Tightness or slackness of gauge whether any indication exists about shifting of wheel on the axle. Note: It must be ensured that the back surface of wheels is cleaned thoroughly before measuring the wheel gauge in order to avoid erroneous readings. In case the wheel gauge is more than the permissible tolerances, there would be a possibility of a relatively new wheel hitting the nose of a crossing, as the wheel gauge is one of the parameters which decide the Clearance at the check rail opposite the nose of the crossing (Fig.) Check rail clearance > Track gauge – (Maximum wheel gauge + flange thickness of new wheel) If, therefore, the wheel gauge is more, the check rail clearance would have to be less than what is actually provided as the standard, if damage to nose is to be avoided. If, however, the wheel gauge is less than the minimum value there would be a possibility of the wheel hitting at the back of a tongue rail while passing through the switch flange-way gap, and thus damaging the tongue rail.The variations in wheel gauge after lowering the coach body on wheels was examined by RDSO/Luck now and circulated to all Railways vide their letter no. MC/WA/GENL, Dated 27.06.88 as follows: 133

LOCO INSPECTORS COURSE MATERIAL The question of variation in the wheel gauge under no load and loaded Condition has been examined by RDSO. The calculations for the 15 ton BG axle under tare load condition indicates that a variation of about 3 mm in the wheel gauge when measured at the top, at bottom location in the vertical plane is likely to take place due to bending of axle under coach load. This variation in wheel gauge under loaded condition, however, has no bearing on the safety of coach operation. However, if the measurements for wheel gauge are done in horizontal plane passing through the axle then the effect of bending of the Axle will not be there. It is therefore clarified that the wheel gauge tolerances of 1600 ± 2 mm as laid down in IRCA rule book is required to be checked under No- load conditions. Wheel Diameter Measurement of wheel diameters is not prescribed by the Rly.Bd. This is because; the wheel diameters are measured only by workshops and ROH/IOH depots where tyre turning facilities are available. Wheel diameters are not checked during train examination or rake maintenance. Rejection of wheels in service is based only on tyre profile reaching condemning limits when checked with tyre defect gauge. However, very often, wheel diameters are measured on the involved wagons. Measurement of wheel diameter should be done at the centre of the tread by using suitable gauge or calipers. Care should be taken to remove all ballast and other particles sticking to the tread before applying the gauge. The calipers used for wagons and coaches differ, since the width of tyres are different. Wheel diameter measured with wheel calipers when the lugs contact the outer rim of the wheel, the tips of the gauge contact the centre of the tyre. DIFFERENCE IN WHEEL TREAD DIAMETERS The wheel diameter is measured on the tread at a distance of 63.5 mm from the back of the wheel in the case of B.G. Wheel, two measurements viz. across the quarter points, should be taken for each wheel (Fig) When wheels are changed / turned, it should be ensured that the variation in tread diameters does not exceed the maximum permissible limits indicated in Table. B.G On the same axle On the same trolley On the same wagon Four wheeled trolleys 0.5 13 25 Six wheeled trolleys 0.5 6 6 Six wheeled units 0.5 6 6 Four wheeled units 0.5 - 25 Of greater significance is the difference in the wheel tread diameters on the same axle. If the difference exceeds the permissible limits, the larger diameter will always try to traverse a longer path than the smaller diameter which will result in the axle moving persistently angular. A persistently angular running of an axle increases the derailment proneness appreciably. Excessive difference in wheel diameters on different axles of the same vehicle has an adverse effect on buffer heights and slope of the vehicle floor. 134

LOCO INSPECTORS COURSE MATERIAL Tyre Profile The outer periphery of a wheel which comes in contact with the rail is known as tyre profile. The standard tyre profile of B.G. is shown in the Fig. Tyre Profile of a new Wheel the important features of the tyre profile are as under.  A 6 mm chamfer at 45 degrees on outer edge.  This is provided to avoid sharp edges and also prevent small burs (chips of metal) projecting beyond the outer surface of wheel due to spreading of small thin layer on outer periphery of the tyre an upward inclination of 1 in 20 towards inside.  It is provided to ensure that the wheels remain in central position of the track and allows the outer wheel to travel on the higher tread diameter and inner wheel on a smaller tread diameter on curves. Route radius: A root radius is provided at the bottom of the flange. The radius for B.G. is 15mm. Height of wheel flange: The Height of wheel flange is measured from the tread of the tyre. It is kept 28.5 mm for B.G. This height also forms an important part in determining the tyre profile. DEFECTS IN WHEELSETS Wheels defects are thin flange, sharp flange, worn root, deep flange, hollow tyre or false flange, flat tyre etc. Thin flange: Higher oscillations due to increase in wheel play and riding instability on turnouts. Sharp flange: Increase of b in Nadal‘s formula, splitting of Turnouts worn root: Increase of b i.e. flange angle (which will cause Maximum eccentricity of the mounting location on the wheel flange, from the contact point of wheel tyre on rail). Deep flange: Damage to track components such as fish plates, Check blocks in level- xings and turnouts. False flange: Unsafe, while negotiating turnouts. Flat tyre: Cause scabbing of rails, leading to rail fracture. Difference in Wheel Dia: Measured on wheels of same axle, same trolley and same wagons (limits have been laid down). Wheel gauge: Checked at quarter points. Excessive variations (over the limits) would indicate bent axle and irregular running of wheel. Rail interaction with IRS wheel profile results in rapid wear of the flange and root of the flange during initial stages till a wear adapted/worn wheel profile is obtained. Since the wear after the worn wheel profile is obtained in service is considerably less, wheels are now provided with worn wheel profile as shown in fig. The condemnation limits for these wheels will remain similar to those of IRS wheel profile according to IRCA Part III & IV. 135

LOCO INSPECTORS COURSE MATERIAL Intermediate Worn Wheel Profile for Goods Stock RDSO‘s Drg. No. X Y ZR 38.5 25 11.5 WD-89060/S2Alt.2 35.5 22 10 33.5 20 9 Intermediate Worn Wheel Profile for Coaching Stock RDSO‘s Drg. No. Speed in kmph X Y ZR ≥ 110 38.5 25 11.5 WD-92082 <110 35.5 22 10 <110 33.5 20 9 When such a profile gets worn, it may reach condemning limits in Reference to any one or more of the following conditions :  Thin flange  Sharp flange  Worn root  Deep flange  Hollow tyre or false flange The above terms denote that the wheel has reached the condemning limit in the particular parameter. The dimensions which delineate the condemning limits have been given in the following Para. In actual practice however, the above condemning limits are checked by a tyre defect gauge illustrated in Fig. (it may be mentioned that each type of wheel profile has its own tyre defect gauge). THIN FLANGE When the flange thickness (B.G. wheel) reduces to less than 16 mm, the condition is called thin flange (Fig.) Thickness of a flange is normally reckoned at a distance of approximately 13 mm from the flange tip for B.G. or M.G. wheel. For coaches of mail/express this limit is 22 mm instead of 16 mm. Effect on Safety A thin flange implies greater play between the wheel set and the track which increases derailment-proneness as under:  Oscillations increase due to greater play, adversely affecting Y & Q.  angularity of axle increases Besides, if the flange is too thin, the back of the wheel may damage the tongue rail while passing through the switch flange way gap of points and crossing particularly with curved switches. 136

LOCO INSPECTORS COURSE MATERIAL Minimum switch flange-way gap is calculated from the formula: Switch flange-way gap < Track gauge – (minimum wheel gauge + minimum flange thickness) If the flange is thinner than 16mm, it would require a correspondingly greater flange-way gap which may not be actually available at site, resulting in possibility of damage to the tongue rail. SHARP FLANGE When the radius of flange tip reduces to less than 5 mm (B.G. or M.G.) The condition is called sharp flange (Fig.) Effect on safety Derailment proneness increases through the following:  µ Increases due to change in geometry of the wheel flange, resulting in greater biting action of the wheel flange along the rail head edge;  Positive eccentricity increases even with the same value of axle angularity;  A sharp flange may split open slightly gaping points while traveling in facing direction, or may mount over a µslightly chipped tongue rail which presents a square surface to an approaching wheel. WORN ROOT When the radius of the root curve reduces to less than 13 mm (B.G. or M.G.) the condition is called worn root (Fig). It is attendant with increase in the flange angle i.e. increase in value of . Effect on Safety Positive eccentricity increases even with the same value of axle angularity. increases owing to reduction in the taper of the wheel flange i.e. owing to increase in value of . 137

LOCO INSPECTORS COURSE MATERIAL DEEP FLANGE When the depth of the flange, measured from the flange tip to a point on the wheel tread (63.5 mm away from the back of B.G. Wheel or 57 mm away from back of M.G. wheel) becomes greater than 35 mm (B.G.) or 32 mm (M.G.) the condition is called deep flange (Fig) Effect on Safety In this condition, the wheel flange coupled with vertical wear of the rail head would tend to ride on the fish plates and check/distance blocks and thus strain and damage the track components. FALSE FLANGE/HOLLOW TYRE When the projection of the outer edge of the wheel tread below the hollow of the tyre exceeds5mm then the outer edge of the wheel is called false flange, and the worn tread is called hollow tyre (Fig.) Effect on Safety A false flange may spilt open points while travelling in trailing direction, as the false flange may tend to get wedged in between the tongue rail and the stock rail as shown in Fig. While negotiating the crossing portion, the wheel going across the wing rail would get lifted as instead of travelling on the tread portion it would travel on the false flange during the duration the wheel travels across the wing rail. This will make the wheel to suddenly lift up and drop down near the nose of the crossing, thus creating conditions favourable to derailment, apart from possible damage to the crossing portion (Fig.) 138

LOCO INSPECTORS COURSE MATERIAL Particularly, on diamond crossings, where the check rail guidance is already very small, such situation would render the wheel appreciably derailment-prone. Observation after measuring the profile with tyre defect gauge The profiles of the wheel tyres are checked by applying the tyre defect gauge and the condition recorded as good or rejectable. As per Rly.Bd instructions, ** The wheel profile is to be checked with tyre defect gauge only (Ref: IRCA Part.III Rule No.3.2.2.(d) and 4.18.1.Plate No.57 to 66). Thin Tyre When Thickness of the Tyre has gone below condemning size, there is a chance of bursting/cracking of tyre throughout the periphery, resulting in derailment. FLAT TYRE The maximum permissible length of flat on the wheel tyre is: Broad Gauge : i) Goods stock, IRS coaching stock 139

LOCO INSPECTORS COURSE MATERIAL ii) For BOX, CS, BCX, BOBX, BOBS 60mm BWT, BWH, BWL, BOI, BOX Mk For BOX, CS, BCX, BOBX, BOBS BWT, BWH, BWL, BOI, BOX Mk I & II BRH and BRS type wagons iii) Coaching stock (ICF, BEML) & Locos 50mm Wheels having flats on tyres cause high dynamic augments on the rails. In fact the rail stresses may get increased by as much as 150% i.e. 2.5 times particularly at slow speeds of 20-25 km/h. In sections, therefore, for Instance suburban sections, ghat section etc. Where the incidence of flat tyres on the rolling stock is quite high owing to severe braking action, a greater incidence of rail fractures can be expected. More awareness should be inculcated in all the staff so that as soon as they observe a particular rolling stock making a repetitive hammer - like sound indicating the presence of flat tyre, they should report the number of the rolling stock to the officials concerned. OTHER WHEEL DEFECTS The wheels sets shall be inspected for the following conditions and action taken as indicated for each condition: Shattered Rim (Fig. ) A wheel with a fracture on the tread or flange must be withdrawn from service. This does not include wheels with localized pitting or flaking without presence of any rejectable condition. 140

LOCO INSPECTORS COURSE MATERIAL Spread Rim (Fig.) If the rim widens out for a short distance on the front face, an internal defect may be present. Spreading of the rim is usually accompanied by a flattening of the tread, which may or may not have cracks or shelling on the tread. Shelled Tread (Fig) Shelling can be identified by pieces of metal breaking out of the tread surface in several places more or less continuously around the rim. Shelling takes place when small pieces of metal break out between the fine thermal checks. These are generally associated with small skid marks or ‗‗Chain Sliding‘‘. Such wheels should be withdrawn from service and sent to workshop for re profiling. Thermal Cracks (Fig) Thermal cracks appear on a wheel tread due to intense heating of the wheel arising out of severe brake binding. Such cracks occur on the tread and generally progress across the tread in a transverse & radial direction. Such wheels may be identified by presence of flats (even within acceptable limits) and severe discoloration or blue black heating marks on the tread. Heat checks (Fig.) Thermal cracks are deeper and need distinguished from superficial cracks visible on tread or adjacent to the braking surface. These are called heat checks, which are usually denser than the thermal crack. Heat checks are caused on the tread due to heating and cooling cycles undergone by the wheel during normal braking. Such wheels do not need to be withdrawn but should be carefully distinguished from the rejectable thermal cracks. 141

LOCO INSPECTORS COURSE MATERIAL ROLLING STOCK PARAMETERS The parameters to be recorded as per Rly Board pro-forma are given in a separate table. Some measurements which are not prescribed by the Rly.Bd are also taken just as a matter of convention. It has to be remembered that unlike the track parameters which are generally taken on track undisturbed in the accident, the rolling stock measurements are taken on rolling stock which have derailed and got dragged on sleepers and ballast. Separate measurement tables are provided for wagons and coaches. Rolling stock details regarding all derailed vehicles should be given except:- 1. Where vehicles have derailed due to locomotive derailed. 2. When the first derailed vehicle is obvious from examination of marks on wheel then the details for first derailed vehicle need only given. 3. When the obvious and indisputable cause is sabotage or an obstruction on track. 4. Brake power 5. In the case of collisions, passing of signals at danger etc, the brake power has to be recorded at the earliest. In enquiries conducted by Commissioner of railway safety, brake power on the formation has to be indicated along with braking force in tonnes. Hence it becomes mandatory to record brake power. 6. Testing of brake power should be done by recharging the air pressure and reapplying the brakes. If this is not possible, it should be seen from the polished marks on pistons of the brake cylinders indicating that the cylinders were operative. 7. In bogie mounted stock, one inoperative cylinder will reduce 25% of brake power of the particular coach. 8. In under frame mounted stock, this will reduce 50% of brake power on the coach. 9. In wagon stock, it will reduce 100% brake power of the wagon. NEW TYPE OF WAGONS Following are the new type of special wagons for different purpose – BLCA/BLCB Low platform container flat wagons, light weight, all welded skeleton design under frame for an optimum tare to payload ratio, 840 mm wheel dia, A&B cars with AAR ‗E‘ type CBC on raised ends of ‗A‘ cars and use of slackness draw bar system on the inner ends of ‗A‘ cars and on all ‗B‘ cars, tare weight, ‗A‘ cars 19.1 t ‗B‘ cars 18. 0 t, pay load 6l t.Fit to run 100 km/h. BOXNHA Higher axle load wagon suitable for 22.1 t axle load and 8.25 t/m TLD for coal loading. Payload per rake shall increase to 3783 t as against 3411 t. In the existing BOXN wagon resulting in 11% increase in throughput per rake. Fit for 100 kmph Tare weight=23.17 t, Payload = 23.17 t Pay Load = 65.13 t BOXNCR Use of corten steel in place of mild steel for the manufacture of BOXN wagons has resulted in arresting the problem of corrosion only to a limited extent. In order to reduce the problem of corrosion substantially, 3CR12 stainless steel has been used in the manufacture of BOXNCR 142