1. Report on Visit to USA and Australia in Connection with Dedicated Freight Corridor

2. The Core Group
Board (ME) has nominated a core group for finalizing the technical Specifications pertaining to track and bridges, consisting of :
EDCE(P), EDCE(B&S) & ED/W from Railway Board,
ED/Track & ED/B&S from RDSO and
Dean from IRICEN.

3. The Core Group The terms of reference of the core group are:
Review the genesis of Maximum Moving Dimensions on IR and also identify factors limiting its relaxation on the existing network.
Compare standards presently prevalent on IR with those obtaining on some of the major freight railway system world over.
Study international experience in rolling stock designs with a view to determining their relevance to both existing as well as future traffic streams of IR.

4. Terms of Reference The terms of reference of the committee are:
Recommend and optimal Maximum Moving Dimensions for the Eastern and Western corridors of the DFC project and other new lines that could be taken up in future.
Recommend the Maximum Moving Dimensions on feeder routes for Eastern Corridor and Western Corridor keeping in view running of 25 tonne axle load wagons of coal and steel traffic on Eastern Corridor and double stack containers on Western corridor.
Suggest an implementation strategy for upgrading feeder routes on the existing IR network to standards proposed for feeder routes.

5. The Sub-Group
A sub-group of the committee consisting of following officers was deputed to USA and Australia to study the implementation of heavy axle load in railway systems of these countries.
Shri V. K. Jain, EDCE/Planning, Railway Board
Shri Anirudh Jain, ED/Track, RDSO
Shri P. K. Sanghi, ED/Works, Railway Board
Shri Suresh Gupta, Dean, IRICEN

6. Visit of the Sub-Group Places Visited in USA:
During the 5 days’ stay in USA the study team visited the following firms:
M/s.Zetatech Associates at, Cherry Hill near New York
TTCI at, Pueblo
BNSF at, Los Angeles
ALAMEDA Corridor at, Los Angeles and
APM Terminal at, Los Angeles

7. Visit of the Sub-Group Places Visited in Australia:
Australian Rail Track Association, New Castle.
Transport Management Group, Sydney.
Queensland Railway, Brisbane.
Freight Facility of QR, Acasia Ridge.

8. US Railroads and visit to Zeta Tech Associates
Track km is about 2 lac 75 thousand km.
Most US Railways are privately owned and runs only freight trains.
AMTRAK operates all US long distance passenger trains.
Rail Road employment has fallen from 4 lac 50 thousand workers in 1980 to 1 lac 55 thousand in Average annual wage is 62 thousand dollar per annum.
Track gauge is 1435 mm.
Economic regulation of US Rail Road is the responsibility of the Surface Transportation Board (STB).
Safety regulation is the responsibility of the Federal Rail Road Administration (FRA).

9. US Railroads and visit to Zeta Tech Associates
Association of American Rail Roads (AAR) is a private trade association and its principal roles are to set mechanical standards for rolling stock, settle accounts between multiple rail carriers, sponsors rail road related research etc.
USA is running double stack container since Its axle load is 30 T, although a number of Rail Roads have begun purchasing stock with 32.5 and 35.5 designed axle load. But main axle load is 30 T
Traction is diesel.
Structurally 60 kg rails are sufficient to support 30 T axle load. However, USA is mainly using 67 – 71 kg rails on timber and concrete sleepers.
On timber sleeper, spacing is 20” from centre to centre and on concrete sleeper, spacing is 24” from centre to centre.
Hardness of the rail is 380 BHN.

10. US Railroads and visit to Zeta Tech Associates
Rail grinding is must for higher axle load operation. One machine with 120 stone is able to grind about km in a year. Operational speed is 20 kmph. Mainly grinding has been outsourced.
Rail lubrication on curves is essential.
Thick Web Switches with swing nose crossing is essential.
Elastic fastening is mainly safe lock (e-clip).
There are about number of rail fractures per year.
Number of accidents on rail fracture account is about 100.
Track is inspected by a staff twice a week on freight route.
TRC – 3 to 6 months depending on traffic density.
No regular inspection by Supervisors or officers.
Hard ballast is used and ballast cushion is more than 300 mm.

11. Transportation Technological Centre Inc (TTCI), Pueblo
A large number of research projects regarding rail hardness track fittings, ballast and bridge monitoring are in progress at TTCI.
TTCI has developed laser based Rail Flaw Inspection System. This will cover the entire rail cross-section at a speed of 32 kmph.
TTCI has developed a proto type of Ultrasonic Crack Wheel Detection System. This system is capable of inspecting the wheel at a speed of 8 kmph.
TTCI has developed proto type laser based Ultrasonic Crack Axle Detection System. This can detect any defect in axle body at a speed upto 32 kmph.

12. BNSF Railways, Los Angeles
Average length of train is 7000 feet which is going to be extended to 8000 feet.
Train load is to tonne.
Entire Habard yard is covered by 22 Video Cameras and visual view is available in Control room. This helps in safety.
50% of security has been outsourced.
Commodities had been divided in high density and low density. Low density commodity is being moved on wagons with articulated bogies. Fuel saving is 10 – 15%.
Truck chassis can be directly loaded on wagons chassis are carried per train.

13. APM Terminal and PIER 400, Los Angeles
This is owned by MAERSK, an International Agency dealing in container movement.
It deals TEUs per week cameras are provided to monitor the entire activity on PIER.
There are 12 tracks of 2200 feet length. Generally a single train of 7000 feet length is accommodated on 4 lines.
Entire operation is computerized.

14. Alameda Corridor, Los Angeles
This is passing through heavily habitated area and connecting to ports. Total length is about 20 miles, out of which, 10 miles pass through a trench.
This was constructed in less than 4 years ( ) at a cost of about Rs. 2.2 billion dollar.
There are 3 lines.
Rail section is 136 LB (67 kg) on concrete sleeper.
Lines are bi-directional.
Track is inspected by a staff twice a week. No regular inspection by Supervisor or Officer.
AREMA standard is being followed in inspection.

15. Australian Rail Track Corporation, Sydney
Total length of track under ARTC is about km.
Total number of employees is about
For controlling overloading, motion weight bridges have been installed immediately after loading point. In case any wagon is found to be overloaded, excess material is removed there itself and no overloading wagon is allowed to go.
Rail grinding is a normal feature and done through Service Contracts.

16. Australian Rail Track Corporation, Sydney
For sharp curves of radius less than 400 m, grinding is done after passage of 10 GMT and for straight track, grinding is done after passage of 20 GMT.
CWRs are continued through bridges.
Their Bridge standards are given in Australian standard for Bridge Design AS 5100 – 2004.
Clearances between MMD and line side structures are determined based on Kinematic envelop. Generally, clearance between static MMD and line side structures is more than 600 mm.

17. Transport Management Group, Sydney
Australia is running 40 t axle load wagons in iron ore routs in BHP (Billiton).
The work of segregating freight and passenger traffic is presently going on.
Iron ore wagons are conventional 3 piece bogies.
They are using a software for developing kinematic envelope.
There are around 100 railway companies in Australia.
Double stack containers are running between Perth and Broken Hill.

18. Transport Management Group, Sydney
Queens Land Railways is running upto 150 kmph on Narrow Gauge (1067 mm)
Coal traffic is having 30 MT axle load and they are thinking of 32.5 MT.
Rail grinding is a must beyond 25 T.
By proper grinding and managing wheel & rail profile life of rail can be doubled

19. Queensland Railway, Brisbane
QR has approximately 9500 km of narrow gauge, standard gauge & dual gauge track throughout the state of Queensland. But the whole of 26 tonnes axle load route is on narrow gauge (1067 mm).
QR is the biggest mover of freight in Australia, transporting almost million tones in 2005.
QR operates 1000 train services daily and moves more than 4,40,000 tonnes of freight.
QR transports commuters on long distance and metropolitan suburban journeys each day.

20. Queensland Railway, Brisbane
QR operates rolling stock ranging in axle load size from to 26 tonnes.
QR operates the innovative tilt train which can travel at speeds up to 160 km.
Centre to centre track spacing is 4.2m minimum.
The complete track is on Continuous Welded Rails (CWR) including those on bridges.
QR has got some lines of dual gauge track on concrete sleepers with three rail seats.
In Metro rail also grinding is being done for noise purpose.
Swing nose crossing is better for heavy axle load operation.
Length of one train is 1800 m, train loads are in range of Tons, 6 X 4000 HP locomotives haul these trains.
There are no passenger services on heavy axle coal lines.

21. MMD for DFC
Dedicated Freight Corridor (DFC) has been announced to be constructed in Howrah-Delhi and Mumbai-Delhi sectors.
The axle load projected to run on this DFC is 30 tons.
With most of the traffic expected to be carried on this DFC consisting of low density commodities like Fertiliser and Coal, there is a need to enlarge the Maximum Moving Dimension (MMD) so as to accommodate sufficient quantities to generate required axle load.

22. Inter-operability Requirements
Looking at the DFC in isolation, there shall not be any problem in increasing the MMD to whatever extent.
But the wagons designed to run on the new corridor will have to run on existing system either when they are running empty or in the originating and destination spokes.
This necessitates a study of our existing SOD and to identify the means to progressively adopt larger, wider and higher, wagons so as to fulfill the objective of carrying higher axle loads.

23. Existing MMD

24. MMD for Dedicated freight Corridor

25. Track Side Structure Profile for Feeder Routes

26. Track Side Structure Profile for Dedicated Freight Corridor

27. Clearance between Moving Dimension and Fixed Structure
The clearance between Moving Dimensions and Standard Dimensions (Fixed structure) depends primarily on the lateral and vertical movement of the vehicle.
Profile of a rolling stock drawn after taking into account the lean, swing and sway etc. is known as Kinematic Profile.

28. Clearance between Moving Dimension and Fixed Structure
The clearance between Static and kinematic profile is required to be enhanced further to take care of:
a passenger or his luggage projecting out of a moving train,
freight stock running with bulging/ open doors,
track being out of alignment and
lean of the line side structures etc.

29. Track Tolerances for Clearance Purposes
Factor
Expected tolerances
Straight Track
<300 m Radius
Rail side wear
± 5
+ 25, - 5
+ 25, -5
Gauge widening
± 0
+10
Gauge (from 1676 mm)
± 20
± 25
Track alignment (from design)
± 50
± 75
Cross-level (from design)
± 30
Rail Level
± 100

30. Possibility of Increasing the Height
Height of a wagon is restricted by Cover Over Platform at its edges and OHE & other structures at the center.
Thus, height of the wagon at sides can not be raised beyond 3735 mm, unless COPs are surveyed and modified.
Similarly, at center, this may be raised beyond 4265 mm, only after survey and modifications to the structures/OHE.

31. Feasibility of running larger wagons on existing system
Indian Railway’s have experience of running BOBR wagons, with a width of 3500 mm.
This experience shall be utilized to decide the width of new wagons to be manufactured for DFC with inter-operability in mind.
However, increase in width alone may not meet the volume requirements.

33. Infringements on Feeder Routes, Outside Stations

34. Infringements on Feeder Routes, Inside Stations

35. Infringements on Feeder Routes, for Structures permitted under Sch-II

36. Comparative MMDs and Fixed Structure Gauges- AAR V/s IR

37. Feasibility of Larger Rolling Stock on Feeder Routes
Due to constraints of existing structures, it may not be feasible to run one standard MMD on all feeder routes.
It is the practice in US railroads and in Australia to have different MMD for different commodities and run them on identified corridors, cleared for them.
We can adopt a similar, commodity based approach for different feeder routes.

38. Feasibility of Larger Rolling Stock on Feeder Routes
In US, width is fixed as 3250mm (10’-8”) and the height varies, maximum being 6150mm (20’-2”) for Plate H. Clearances to track side structures are accordingly fixed.
MMD Type
Width ft
Width mm
Height ft
Height mm
Plate-B
10’-8”
3250
15’-1”
4600
Plate-C
15’-6”
4725
Plate-E
15’-9”
4800
Plate-F
17’-0”
5180
Plate-H
20’-2”
6147

39. MMD in AAR Plate-H for Double Stack Containers

40. AAR Fixed structure Schedule for Plate-H

41. Feasibility of Larger Rolling Stock on Feeder Routes
In Australia, both width and height of wagons vary, depending on the route on which they are running.
There are specified clearances for track side structures for each type of Rolling Stock.
Australian Railways have 6 different MMDs. Called Rolling Stock Out Line - ‘A’ to ‘F’

42. MMD and Fixed Structure Profiles for Rolling Stock Outline A on ARTC

43. MMD and Fixed Structure Profiles for Rolling Stock Outline E on ARTC

44. MMD and Fixed Structure Profiles for Rolling Stock Outline F on ARTC

45. Feasibility of Running Larger MMD on Existing System
Following inference can be drawn:
A wagon can be constructed, up to an MMD width of 3500 mm, to operate on feeder routes with suitable precautions.
Height at center of these wagons shall be restricted to 4495mm and at side to 4205mm.
These wagons shall be door less or have only sliding doors.
Routes shall be identified and modifications carried out to COP and over head structures/OHE, where ever required.
These wagons shall be confined to identified and modified routes only, so as to provide vital links to DFC.
On routes where Larger MMDs are required due to traffic like Double Stack Containers or Auto racks, route specific MMD may be specified.

46. MMD for DFC
Proposed MMD to be adopted on Dedicated Freight Corridor shall be as follows:
Width: 3500mm.
Height: 7100mm.
Sides shall be tapered inwards from a height of 4880 mm to give a top width of 3200 mm.
This MMD shall be the MMD for DFC to be adopted for such services as are confined only to the DFC.

47. MMD for Inter-operability
Running of larger wagons on existing network is possible only on specific sections, built as per Schedule–I after removing all existing infringements permitted under schedule-II and imposition of suitable speed restrictions wherever actual clearance becomes less than 380 mm.

48. Formation
Formation width in embankment/ Cutting and centre to centre spacing shall be as follows:
Single line 6.85m (As existing)
Double line 12.35m
Centre to centre spacing of tracks 5.50m
Suitable thickness of sub-ballast/ blanket shall be provided as site requirements.

49. Grades and Curvature Curvature should be limited to 700m (2.5 degree).
Ruling Gadient shall be decided based on topography, loads to be carried and the haulage capacity.
1 in 150 compensated, except at isolated places where cost of providing such a gradient is exorbitant may be considered.

50. Comparative Track Parameters
Item
IR, Present Status
North American Railroads
Australian Railroads
Gauge
1676 mm
1435 mm
1067mm and 1435 mm. In BHP: 1435 mm.
Axle Load
22.82 MT
30 MT
25 MT, 30 MT on some dedicated freight lines, 37.5 MT on BHP Billiton Iron Ore line.
RAIL - Weight
60 and 52 kg per m.
136 RE i.e. 68 kg per m.
60 kg per m. 68 kg per m in dedicated freight lines for 30 MT and 39 MT axle loads
Rail - Grade
260 BHN
Premium Rail with 380 to 400 BHN
340 to 380 BHN,
Premium Rail with 380 to 400 BHN in BHP.

51. Comparative Track Parameters
Item
IR, Present Status
North American Railroads
Australian Railroads
Sleepers
Mono Block PSC
Mostly hard wood, Mono Block PSC in some cases.
FASTENINGS
Elastic, Pandrol Type
Sleeper Spacing
60 cm, 1660 per km
50 cm, 2000 per km in case of wooden sleepers and 60cm or 1660 per km for PSC

52. Comparative Track Parameters
Item
IR, Present Status
North American Railroads
Australian Railroads
Ballast
Crushed Rock, LA abrasion value 30%
Crushed Rock, LA abrasion value 20%
RAIL GRINDING
Not existing
Implemented fully, need based concept
Implemented fully in a need based concept on dedicated freight lines. Once a year on other lines.
RAIL INSPECTION
By manual USFD, need based concept.
USFD car under need based concept averaging once in 3 to 4 months.

53. Track Structure
Survey of current practices, carried out by JRP-2, initiated by World Executive Council of UIC indicates the following relationship between Rail Section and Axle Load:

54. Track Structure
An analysis of the above Chart provides following insights:
Larger and heavier rail sections are being used for higher axle-loads, world over.
Currently, standard rail section for medium (20t to 30t) axle-loads appears to be the 60kg/m.
Smaller sections currently in use on some railways will, probably, eventually, be replaced by heavier sections.
Railway systems running axle-loads in excess of 30t use 68kg/m rail sections.
One railway system uses 75kg/m rail section for axle-loads lower than 30t. This is because of problems with rail fracture at extreme low temperatures.

55. Track Structure
The Survey also indicates that rails with Higher BHN are being used for higher axle loads:

56. Track Structure Choice of suitable rail section: Dimensions Unit
UIC 60
136 RE
136RE-CN
136RE-OPT
UIC 68
Section Weight
kg/m
60.00
67.42
67.71
67.36
68.00
Rail Height mm
172.00
187.74
186.53
177.00
Foot Width
150.00
152.40
 150.00
Head Width
72.00
74.61
Area
mm2    
Ixx
cm4  
Zxx
cm3
335.50
387.00
390.00
397.00
359.80 
Iyy
512.90
600.00
602.00
636.50 
Zyy
 68.40
79.00
84.90 

57. As per the survey larger diameter wheels are used for higher axle loads.
Wheel diameters have been associated with axle-load for the combined reasons of heat dissipation and contact stresses and the relationship of these parameters is shown below :

58. Wheel Diameter:
Generally, following wheel diameters are adopted for various axle loads:
Axle load Range
Wheel Diameter (mm)
Less than 22t
864mm
22t to 37t
915mm
35t and higher
965mm
Wheel diameter will have to be decided in advance to design suitable track structure.

59. Track Structure Rails:
60 kg, 90 UTS rails can withstand a maximum of 25 t axle loads at 100 kmph.
Rail stress calculations for 30 t axle load at various speeds indicate that a section higher than 60 kg 90 UTS is required.
For 30 t axle load, 68 kg (90UTS ) rail section shall preferably be used.

60. Track Structure cont. PSC sleepers:
Existing PSC sleepers have been designed for 22.5 t axle loads. They can withstand axle load of 25t, as checked in RDSO.
For 30 t, new design has been done. Outer shell dimensions have been changed along with HTS configuration.
The PSC sleepers have also to be designed for Points & crossings, Level crossings, SEJs, Bridge approaches etc.
It is possible to use the existing plain track sleeper with increased Sleeper density for 30 ton axle load. Further studies are required, with respect to rubber pad and maintenance tamping.

61. Track Structure Cont. Elastic fastening system:
The elastic fastening system being used is suitable only for present level of operation i.e t axle load. Based on experience, they may be continued for loads up to 25 t.
The design parameters for heavier axle load need to be fixed for the fastenings system and fastenings designed accordingly.

62. Track Structure Cont. Points & Crossings:
The existing points & crossings layouts and SEJ’s are suited for 22.9 t axle load.
For heavier axle load Thick web switches, Swing nose crossing, Improved SEJ may be required as per the existing practices in some other world railways.

63. Need for Rail Grinding

64. Contact Between Wheel and Rail
Wheel centrally placed on the track

65. Need for Rail Grinding
Hertzian Normal contact stress distribution over contact areas

66. Need for Rail Grinding Cont.
The normal contact stress on the top of the rail and wheel tread surface depends on the wheel to rail load, wheel and top of rail radii, and the interacting materials properties.
Hertz’s theory is valid for contacting surfaces under the following assumptions:
The contacting bodies are homogeneous and isotropic
The contacting surfaces are frictionless
The dimensions of the deformed contact patch remain small compared to the dimensions of contacting
bodies and principal radii of curvature of undeformed surfaces
The contacting surfaces are smooth

67. Need for Rail Grinding Cont.
When a wheel set is moving in a curve, if the yaw angle becomes large, it is possible to have the wheel contacting the rail at two different points.
Two-point contact results in two contact patches:
(A) on the rail crown and
(B) at the gauge side of the railhead.
Because of the wheel to rail angle of attack, the gauge side contact patch is moved forward.
Increasing the angle of attack results in an increase of the distance between contact patches and thus an increase in creep forces.
In the flange contact zone of the high rail, a level of contact stress of 3000 MPa is common.

68. Need for Rail Grinding Cont.
Location of the Contact Zones
under Two-point Contact Conditions
(FA=110 kN, Fb=66kN )

69. Need for Rail Grinding Cont.
Typically, contact stress on the top of the rail running surface (region A) range between 1300 and 1700 MPa.
The increase in wheel load increases contact stress on the top of rail surface.
Hollow wear of the wheel tread results in high contact stress. Contact stress could rise to 6000 MPa for a 2 mm hollow worn wheel.

70. Need for Rail Grinding Cont
Both the magnitude and distribution of contact stress is significantly influenced by wheel/rail profiles and whether single - or two-point contact conditions exist.
Conformal profiles tend to result in larger contact patch having decreased levels of contact stress as compared with non-conformal profiles.

71. Effect of Traction on Contact patch

72. Need for Rail Grinding
Optimized wheel and rail profiles are those which provide for the best performance for a given application.
Performance is generally judged on the following criteria:
Resistance to Wear
Resistance to Fatigue
Resistance to Corrugation Development
Minimization of the Ratio of Lateral to Vertical Truck Forces
Minimization of Noise
Maximization of Truck Stability

73. Need for Rail Grinding
Recommendations for optimizing wheel/rail profiles in terms of the contact stresses:
Avoid contact stress that is greater than three times the strength of material in shear.
Distribute contact points across the wheel tread and railhead by profile design and rail grinding so that not only are the high rail, tangent, and low rail profiles different, but in tangent track there is more than one contact band
Vary gauge clearance in tangent track intentionally.

74. Need for Better USFD Testing
With spate in Gauge corner cracking, improved USFD techniques will be required.
USFD shall be capable of Covering > 94% of head, entire web and area of foot under the web.
Sperry’s USFD has the above capabilities. Efforts are on in RDSO and TTCI to develop better methods.
Rate of generation of flaws and rate of growth of flaw observed in successive rounds of USFD testing in different section will decide the frequency of testing.

75. Need for a Better Suspension Bogie
The vehicle, when moving forward on the track, experiences vibrations of varying frequencies which excite the various modes of the vehicle structure, body and the payload.
The dynamic modes are generally in bounce, roll, pitch, nosing, and sway.
Any railway vehicle requires at least two wheel sets. The manner in which these wheel sets are coupled to the vehicle has a significant influence on the performance of the rail and the wheel.

76. Need for a Better Suspension Bogie
As a result of vertical vehicle dynamics, Heavy dynamic loading is generated. Dynamic loads as high as 4 times the static load have been recorded.
These Dynamic loads are transmitted from the vehicle through the wheel into the track super and substructure.
Track elements such as rail, rail pads, sleepers, ballast and the sub-ballast layer, are thus directly influenced by the dynamic performance of the railway vehicle.
The typical exciting mechanisms are:
Vehicle body dynamics in the frequency range between 1 and 30 Hz
Out-of round wheels (10 to 20 Hz)
Wheel flats (10 to 20 Hz)
Rail irregularities, such as rail joints and wheel burns/ skid marks.

77. Need for a Better Suspension Bogie
In its simplest form, the suspension of a railway vehicle comprises four springs vertically coupling the four journal bearings on two wheel sets to the body.
The four springs can be designed within the space and for the load of a relatively small and light vehicle.
However, as the vehicle becomes heavier and larger, the ability to accommodate track twist by means of spring deflection clashes with the demands on coupler height differential limits between a loaded and an empty vehicle.
As the carrying capacity of the vehicle increases, the wheel base increases. This leads to increased demands on vertical deflection to accommodate track twist.

78. Need for a Better Suspension Bogie
A Bogie provides solution to the problem caused by increased wheel base.
A bogie is the equivalent of a short wheel base vehicle with a limited but adequate vertical spring deflection to accommodate track twist.
In addition, the carrying center plate is of limited diameter. This coupling can be designed to permit additional track twist by means of providing sufficient side bearer clearance.
The bogie has become standard equipment under railway vehicles.
There are two basic types of bogies; the rigid frame and the three-piece bogie.
Three piece bogie is most commonly used bogie type for freight wagons.

79. Three Piece Bogie

80. Need for a Better Suspension Bogie
The three-piece bogie, comprises two side frames, each resting in a longitudinal orientation, on the journals of the wheel sets.
The side frames support a cross member — the third piece — termed a bolster.
The bolster is fitted with a center pivot, which couples the bogie to the vehicle body.
The three pieces, two side frames and a bolster, are each simply supported beams.
This makes the bogie a statically determinate structure and allows the structure to articulate under conditions of track twist without loosing vertical wheel load.

81. Need for a Better Suspension Bogie
The conventional three-piece bogie has been the standard freight bogie for many years because of its low manufacturing and maintenance costs.
One advantages of this structure for vertical suspension is efficient accommodation of track twist.

82. Need for a Better Suspension Bogie
Three piece bogie has several disadvantages:
it does not have adequate vehicle stability at higher speeds;
it has poorer curving performance that results in higher wear between the wheel flange and the rail gauge corner; and
it may result in derailments due to excessive lateral forces and a high curving resistance.
the side frame forms part of the unsprung mass on the wheelset.
Furthermore, the lateral dynamics of the bogie is not optimal.

83. Need for a Better Suspension Bogie
A suspension arrangement is thus required between the two wheelsets of a bogie, which ensures a virtually pure rolling motion of the wheelset in a curve and adequate hunting stability on straight track.
Such designs are found in self-steering and forced-steering bogie designs.
The main advantages of steering bogies are:
reduced flange and lateral rail wear,
improved lateral to vertical wheel/rail force ratios,
Lower curving resistance, and
better derailment and hunting stability.

84. BRIDGES

85. General
Both in America & Australia most of the Railway Bridges are ballasted deck Bridges
In America most of the bridges are over 100 years old. Based on construction material the length of bridges is as follows:
- Wooden – 18%
- Concrete – 28%
- Steel – 54%

86. General (Cont’d….)
In America about 8 billion dollars are spent annually on replacement of infrastructure (Track & Signals) of this 340 million dollars is on bridges.
Wooden Bridges are mostly small span bridges, thus their number is high. These are being replaced by precast concrete bridges.

87. General (Cont’d…)
Bridge evaluation is done based on visual inspection, study of load spectrum & measurement of strains in critical components.
Rating of Bridge is done based on residual life and capacity to take higher axle loads.

88. RATING OF EXISTING BRIDGES
Each bridge shall be assigned two ratings; NORMAL and MAXIMUM. The stated normal and maximum ratings of each bridge as a unit shall be the lowest of the ratings determined for the various components.

89. RATING OF EXISTING BRIDGES (Cont’d….)
Normal Rating
Normal rating is the maximum load level which can be carried by an existing structure for an indefinite period of time.
Maximum Rating
Maximum rating is the maximum load level which the structure can support at infrequent intervals.

90. Construction of Bridges
Precast bridges are assembled on steel pile group driven into ground to serve as foundation.
These steel piles extends upto the pier cap. Top ends of steel piles, mostly RSJs are embedded into the recess provided in the pre-cast pier cap by grouting.
On the top of pier cap, precast slabs are supported.
Even the wing walls are precast.

91. Construction of Bridges (Cont’d….)
AAR is using precast, prestressed slab & girders in their concrete bridges.
To study the effects of various forces coming from heavy haul, a bridge having two PSC spans of 35’ & 55’ respectively are under testing in TTCI, Pubelo.
Concrete of 90000psi (650 kg/cm2) or higher is used in precast components.

92. DESIGN
There are bridge loading standards on the line similar to IR to which, bridges falling in various classes of rail roads are designed. Most common loading standards are Cooper E-80 & Cooper E90. (Chapter 8,9,15, 19 & 29 of AREMA Manual for Railway Engineering 2003 Volume II,Structures.)

93. DESIGN (Cont’d…)
In general the concept of Eudl is not used in the design of Bridges. Rather the actual axle loads for a certain number of locomotives & wagons are being considered. Loading diagram of Cooer E(80) is indicated in the next slide.

94. DESIGN (Cont’d.)
Loading Diagram

95. DESIGN (Cont’d.)
The following forces are considered for design of bridges.
STEEL BRIDGES:
(1) Dead load.
(2) Live load.
(3) impact load.
(4) Wind forces.
(5) Centrifugal force.
(6) Forces from continuous welded rail –
(7) Other lateral forces.
(8) Longitudinal forces.
(9) Earthquake forces.

96. DESIGN (Cont’d.) Concrete Bridges: D = Dead Load L = Live Load
I = Impact
CF = Centrifugal Force
E = Earth Pressure
B = Buoyancy
W = Wind Load on Structure
WL = Wind Load on Live Load
LF = Longitudinal Force from Live Load
F = Longitudinal Force due to Friction or Shear Resistance at Expansion Bearings.
EQ = Earthquake (Seismic)
SF = Stream Flow Pressure
ICE = Ice Pressure
OF = Other Forces (Rib Shortening, Shrinkage, Temperature and / or Settlement of Supports)
From the above, it appears that for ballasted deck bridges CWR forces are not considered for design.

97. LWR on Bridges
There is no restriction for providing CWR on ballasted deck bridges.
CWR can also be provided on open deck bridges but they require special considerations.

98. Bridge Loading Standard in Australia
Australian Bridge Loading Standards 300 LA Railway Train Loads

99. DEDICATED FREIGHT CORRIDOR
B&S DIRECTORATE

100. NEW CONSTRUCTION:
For construction of new bridges for dedicated freight corridor routes, with axle load of 30t with maximum track loading density of 12 t/m Heavy mineral loading (HM loading) to be followed.
Most of the bridge designs for standard spans for HM loadings are available. However through girders are to be designed for revised MMD.

101. DETAILS OF HEAVY MINERAL LOADING:-
In Heavy mineral loading different combinations of locos and wagons have been taken into considerations. Upto four locos and wagons of 30t axle load have been considered.

102. LOCOMOTIVES Locomotives Single/double headed Triple headed Four headed
Axle load
30.0T
18.8T
Tractive effort
60.0T per loco
45.0T per loco
30.45T per loco
Braking force
25.0T per loco
22.00T per loco

103. TRAIN LOAD Axle load 30.0T Track loading density 12.0T/M
Braking force per axle % of axle load

104. From construction point of view, ballasted deck bridges to be used from maintenance aspect.
Long lasting paint to be used on steel bridges for reduced maintenance.
Modular construction of bridges to be adopted for fast construction and better quality control with high performance concrete.

105. Real time bridge load monitoring systems shall be installed on routes at selected points.
Use of optical fiber communication network for real time remote monitoring of important bridges.
Avoiding piers in canals and nallahs carrying sewage/polluted water having chemicals.

106. DETAILS OF STANDARD BRIDGE LOADINGS
STRENGTHENING OF FEEDER ROUTES FOR 25T AXLE LOADS
DETAILS OF STANDARD BRIDGE LOADINGS
S. No.
Standard Bridge Loadings
Year of Introduction
Loading details 1.
BGML
1926
Axle load : 22.9T
TLD : 7.67T/M
Total TE : 47.6T 2.
RBG
1975
Axle load : 22.5T
Total TE : 75T 3.
MBG
1987
Axle load : 25T
TLD : 8.25T/M
Total TE : 100T

107. For permitting higher axle load i. e
For permitting higher axle load i.e. 25 T on feeder route, existing bridges for superstructure have been checked for actual axle load for loco and wagon and as follows:

108. FITNESS OF STANDARD BGML, RBG AND MBG SPANS FOR 25T AXLE LOAD (60 KMPH SPEED)
S. No.
Standard Bridge Loadings
Details of Standard Spans Fit for 25T Axle Load
For BM
For SF 1.
BGML
Upto 70m
Upto 72m 2.
RBG
Upto 40m
Upto 30m 3.
MBG
100%

109. CONCLUSIONS FOR 60KMPH SPEED
All spans upto 70m of BGML Loadings are fit for 25T Axle Load however span of 78.8m is fit for 50kmph.
All spans upto 30m of RBG Loadings are fit for 25T Axle Load. However 31.9m span is fit for 50kmph speed.

110. For RBG Loading SPANS 47. 3m, 63. 0m and 78
For RBG Loading SPANS 47.3m, 63.0m and 78.8m (all effective) are prohibited, however spans of 47.3m and 63.0m can be strengthened with minimum input while 78.8m RBG standard triangulated girder needs replacement.
All spans of MBG Loadings are fit for 25T Axle Load
Above conclusions are based on the assumption that the sections provided are exactly as per design requirement, whereas actual section provided may be on higher side.

111. Checking of longitudinal forces for running of 25t axle load
Details of design longitudinal forces-
BGML loading – Total Tractive Effort is 47.6T
RBG loading – Total Tractive Effort is 75T
MBG loading – Total Tractive Effort is 100T
Longitudinal forces for wagons with 25T axle load and present available critical locos i.e. coupled WAG9 and coupled WDG4 have been worked out and checked with designed longitudinal forces for different standard loadings. Observations are as below:-

113. COMPARISON OF LONGITUDINAL FORCES BETWEEN STANDARD LOADINGS AND 2WAG9+BOXN WAGONS HAVING 25T AXLE LOAD (9.33T/M T.L.D.)
Span (m)
LF for BGML
(in T)
LF for RBG
LF for MBG
LF for 25T loading
25.6
45.2
60.0
83.3
52.8
31.9
47.6
70.0
100.0
47.3
58.0
77.9
70.4
63.0
66.0
105.3
107.0
78.8
72.9
128.2
123.6

114. CONTD…
i.e induced longitudinal forces for 25T axle load with 2WAG9 locos is more for Standard spans of 25.6m, 31.9m, 47.3m and 63.0m for BGML loading and other spans BGML loading and all spans of RBG and MBG loadings are safe for 25T axle load with respect to longitudinal forces.

116. COMPARISON OF LONGITUDINAL FORCES BETWEEN STANDARD LOADINGS AND 2WDG4+BOXN WAGONS HAVING 25T AXLE LOAD (9.33T/M T.L.D.)
Span (m)
LF for BGML
(in T)
LF for RBG
LF for MBG
LF for 25T loading
13.1
35.5
37.5
50.0
37.0
25.6
45.2
60.0
83.3
59.6
31.9
47.6
70.0
100.0
47.3
58.0
77.9
79.5
63.0
66.0
105.3
107.0
78.8
72.9
128.2
123.6

117. CONTD…
i.e induced longitudinal forces for 25T axle load with 2WDG4 locos is more for Standard spans of 13.1m, 25.6m, 31.9m, 47.3m, 63.0m and 78.8m for BGML loading and other spans BGML loading and all spans of RBG and MBG loadings are safe for 25T axle load with respect to longitudinal forces.

118. To over come this problem the tractive effort of locos have to be restricted to 30t/ loco while running on some spans of bridges designed for BGML loadings.
This limitation will be applicable only if train stops on bridges with restricted spans of BGML loading.

119. MEASUREMENT OF LONGITUDINAL FORCES
The above conclusion has been drawn assuming that 25% dispersion is allowed for longitudinal forces.
Presently actual measurement for dispersion of longitudinal forces on the bridges is not available. A preliminary study by Southern Railway on one bridge with SERC/Chennai has been done using hydraulic jack on a plate girder. This study is very-very preliminary and not simulating the actual train load condition and hence can not be relied upon. Further studies in other Railways i.e. South Eastern and East Coast Railway with actual train load conditions is in plan.
For concluding the actual transfer of longitudinal forces on the bridges detailed instrumentation studies has to be done.

120. MONITORING OF BRIDGES AFTER INCREASE OF AXLE LOAD
We do not anticipate appreciable increase in maintenance efforts for the bridges designed for higher loading.
For existing bridges, where higher loading has been permitted, more close intensive monitoring and instrumentation is required to assess the effect from fatigue and other considerations over years and will require additional maintenance efforts.

121. The instrumentation shall include :-
Strain gauging of every critical member
Measurement of Acceleration
Measurement of Displacement
Such instrumentation shall be done on selected critical bridges of the section. Initially, the recording shall be done for at least every three months for the first two years thereafter it can be reviewed.

122. Frequency of visual inspection also need to be increased suitably.
Such observations shall be continued atleast for a period of 10 years. Thereafter, further decision shall be made based on the output of the observations.
This will decide future course of action with respect to:
required maintenance efforts for the bridge
strengthening/replacement of bridges required, if any. It will provide basis for making future policy and guidelines for increasing of axle loads on the existing bridges.

123. Suitability of substructure for 25t axle load for feeder routes and superstructure for non standard spans to be checked by zonal railways.

124. THANKS