SN

Item

Old Practice

Present Scenario

1

Track renewals

Manually

By machines(PQRS,TRT);increased progress of renewal facilitating replacement of worn out tracked timely before any failure; better quality control.

2

System of maintenance

Manually (MSP was introduced in late sixties)

For ensuring better line and level of track, important routes being tamped by state of art machines like CSMs.  Points and crossings tamping points and crossing on run through lines on A,B,C and D routes.  BCMs row available to do deep screening to improve drainage.  Controlled consolidation of track started by Dynamics Track Stabilizer after ballast cleaning/renewal/tamping.  Efforts also being made to develop light tampers for intermediate attention.

3

Welding

3.1

Reconditioning of points & crossings

Eutectic welding was not developed.

Workshops now exist almost with every PWI on A&B route and almost with every other alternate PWI o other routes to recondition points and crossings.  In-situ reconditioning also started.

3.2

Elimination of Fish Plated Joints.

Thermit welding was not developed.

Stationary Flash butt welding plants, mobile FBWPs, Thermit welding by SKY proved (superior site welding) being extensively used.  Fish plated tracks are being increasingly converted into SWR/LWR, improving riding and safety against fracture at joints besides fuel economy.

4

Optimization of track inputs

Calendar system of maintenance

Computerized track management system has been introduced to optimize the inputs into track maintenance and to monitor various safety aspects of track maintenance.

5

.

Upgradation of track structure

5.1

Ballast profile

Conventional

Profile prescribed for different situations describing ballast cushions, wide/shoulder and shoulder heaping of ballast.

5.2

Fastenings

Conventional

Increasing use of elastic fastenings, even MSLJs on ST sleepers being replaced by elastic fastening on important routes and thereby ensuring on important routes and thereby ensuring better rail grip to sleepers, more safety against creep, fallen keys and gauge widening Elimination of dog spikes and round spikes by rail screws and plate screws to improve vertical holding on wooden sleepers.

5.3

Sleepers

Wooden and Metal

(i)                   Wooden being eliminated on all important routes, increasing use of concrete sleepers.

(ii)                 Higher sleeper density for better track rigidity.

5.4

Rails

90 IBS/75R

Heavier rail section with higher UTS to carry heavier loads Gauge face lubrication of rails providing enhanced safety against derailment on curves.  Use of head hardened rails sleep on grades, sharp curves, etc.  Improved metallurgy of steel, stricter dimensional tolerances, improved manufacturing process, mechanized handling of rails.

5.5

Ballast

No quality control through measurement of physical properties

(i)                   Specification now provide source selection mechanical crushing, radiation and larger size, shape parameters & specific gravity, weathering parameters and control over smaller particles and dust.

(ii)                 Use of sub-ballast now prescribed for higher traffic density and heavy axle routes.

5.6

Points and crossings

i) Built up crossing

ii)Straight switches

iii)Under cut switches

iv) Loose heel

Increasing use of curved switches and those with smaller entry angles 1 in 16 and 1 in 20 Over riding switches

Fixed heel for better stability.

Thick web switches for better safety against lateral loads and also permitting higher speeds.

5.7

Diamond crossing

Wooden/Metal sleepers

Increasing use of TRC sleepers on turn outs.

Straight switches on diamond switches being replaced by curved switches.  Increasing use of movable switch diamond to replace existing diamond crossing.

5.8

Joints

Mostly staggered

Square Joints

5.9

Level Crossings

Running Rail having many holes Wooden sleepers

i)                     Running rail without holes

ii)                   Increasing use of PRC sleepers instead of wooden sleepers.

5.10

Curves

i) Virtual transition length

ii) No concept of can excess

iii)no concept of vertical curve

Safety and comfort considerations being adequately taken care of by providing longer transition curves with smaller cant gradients Excess to 65mm.

Provision of vertical curve at grade separation stipulated.

5.11

Track structure on bridges

Wooden sleepers conventional bearings

Use of  PRC sleepers on approaches; use of elastomeric bearings.

5.12

Other weaker structures.

Water columns,ash pits removed from track on all important routes.

5.13

Ballast less track.

No such concept

Use of ballast less track on tunnels, platform lines and bridges.

5.14

Insulating joints for track circuiting.

Glued insulation joints being used which are far more reliable and strong enough for use in welded track too.

6.

Diagnostic Aids.

6.1

Track measuring system

Use of simpler gadgets

Computer based track recording cars with on board computers and oscillograph and cars.

6.2

Rail flaw detection

No such

USFD machines mounted on trolley and operated by trained staff prior to laying and periodically during service.  Considerable efforts have been made to introduce double rail tester in a big way.

6.3

Minor track works.

By manual means.

During last three decades, many small track machines hae been introduced to produce quality work for maintaining the structurally heavier modern track.

6.4

Fatigue Testing

Not possible.

Fatigue testing of a complete track panel can be done in laboratory by simulating the dynamic loading conditions.

7.

Level Crossings.

7.1

Provision of safety devices.

None existed.

Automatic warning system being introduced.

7.2

Manning of level crossings.

Large Number unmanned.

Large No. of level crossings have been upgraded and manned.

7.3

Signal protection

On very few.

Busy level crossings are being increasingly interlocked and protected by signals.

8

Training systems

Conventional

Modern training gadgets and simulators being increasingly used for training of person.

9.

Bridges

1. Minor bridges upto 6.1m girder being replaced with RCC/PSC slab.
2. Composite girders (9.15m, 12.2m, 18.3m, 24.4m) with ballasted deck.
3. Guard rails on all bridges (including ROB).
4. ROBs replacing level crossings.
5. Introduction of PSC girders 12.2m and 18.3m.
6. *All ROBs with PSC girders, all spans.
7. Welded girders 9.1m,12.2m,18.3m and 24.4m.
8. Replacement of early steel girders.
9. Pathways and foot path on bridges.
10. Resiting man/trolley refuges.
11. Protection frames against OHE lines on FOBs.
12. Rehabilitation of bridges – old arch bridges masonry   structures.
13. Bridge Management System.
14. More scientific estimation of design discharge.
15. Improved design considerations to cater for even the derailment loads.
16. Scientific criteria has been evolved for load testing of old arch bridges.

10.

Formation

-

i) Mechanized compaction of earth work in formation, enabling higher speed and welding of newly laid track.

ii) Formation treatment of weak formation.

iii)More cess width.

11

Yard gradient

1 in 400

1 in 1200