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Push-Pull Freight Trains – A Landmark Innovation In Rail Operations On Chakradharpur Division Of S.E.Railway

By on September 10, 2014

TATA Steel has expanded its capacity from 6.8 mtpa of steel to 10 mtpa.  This was targeted to be in place by 31st March’13.  Consequent upon this expansion, iron ore requirement of TATA Steel has gone upto 17 mtpa which is equivalent to 13 trains per day as against the present requirement of 9.6 trains per day.  Iron ore is loaded from TATA Steel’s captive mines at Joda in Odisha and Noamundi in Jharkhand.  Iron ore is loaded in BOBS wagons(rake of 55 BOBS plus Brake van) with side-discharge facility and is unloaded at TATA Works Site(TWS) served by Adityapur station (ADTP).

Conventional Train Operation System:

Conventional system of train operation, prior to innovative technique, was in place as mentioned below (at loading point):

  • Empty rake supplied at serving station(Joda or Noamundi).
  • Railway engine detached.
  • TATA’s diesel engine attached.
  • Rake taken to loading point, TATA engine shunts during loading.
  • After loading, rake brought to serving station and brake-van reversed.
  • Railway engine attached and train leaves for ADTP station.

Operations at unloading point consisted of following sequence:

  • Loaded rake made over at ADTP Reception Yard and Railway engines detached.
  • Customer’s(TATA Steel) diesel engines attached to haul the rake to one of the four Track Hoppers.
  • On release, rake either moves along the bulb line via West Marshalling Yard & made over to Railways at ADTP or the rake, on release, is brought back to Reception yard and after reversal of brake-van, made over to Railways.
  • MU Railway engines are attached on top and empty rake dispatched, after examination,  to loading point.

Constraints with conventional Train Operation System:

With above system of operation, train turn-round was getting affected due to the following constraints:

  • Repeated attachment and detachment of engines.
  • Reversal of brake-van.
  • Brake release consequent upon application of brakes at the time of detachment of engines.
  • Reduced section capacity due to running of light engines.

Push-Pull Train Operation System:

To feed 13 iron ore rakes per day to TATA Steel Plant at Jamshedpur, with the existing fleet of BOBS rakes was a challenge and an opportunity. The solution was to drastically reduce turn-round time by adopting innovative technique.  Push-pull freight train operation was the answer in which the multi-engine used in the front was split with one engine each attached in front and rear.  The brake-van got eliminated.  In its place one more BOBS wagon was added.  Initially, both the engines are to work in tandem – the front engine pulling and the rear one pushing with co-ordination established through pressure gauge and walkie-talkie.  Later, with ongoing trials of loco trolls completion, both the engines shall be synchronized from one cab leading to better control on run and saving of one set of crew.

The push-pull operation required matching development both at loading and unloading points.  At loading end, requirement was for a Rapid Loading System(RLS) with facility to receive empties directly on to the loading line, spotting wagons under the chute by using engines already attached to the rake at both ends and dispatch after completion of loading.  At unloading end, requirement was for OHE arrangements covering Track Hoppers enabling direct placement of loaded rakes over Hopper with incoming engines, spotting on Hopper and despatch after completion of unloading.

This push-pull system which is so far confined to suburban passenger operations through use of EMUs, DMUs and MEMUs, has been put to successful trials in the period from Oct’12 to Jan’13 on CKP division of S.E.Railway with commissioning of TATA Steel’s Joda East Direct Entry(JEDE) siding.  System is in regular commercial operation now w.e.f. June’13 and rakes are moving seamlessly between Joda/Noamundi mines and Tata Steel Plant.

Impact of push-pull system:

    • Reduction in turn-round time:
      System Loading end Unloading end Running time (in Hrs.) Total turn-round (in Hrs.) Rakes required to feed 13 rakes/day
      Empty arrival to load departure (in Hrs.) “Load arrival to empty departure(in Hrs.)
      Conventional 8.43 14.53 16.13 39.49 21.3 ≈ 21
      Push-pull 4.00 8.00 16.00 28.00 15.1 ≈ 15
    • One more wagon put in place of the brake-van resulting into additional loading of 69 t per rake i.e. 897 tpd. Brake-vans released for use elsewhere.
    • Turn round of BOBS rakes reduced from 40 to 28 hrs. No need to induct 6 more BOBS rakes into TATA iron ore circuit to meet 10 mtpa capacity.
    • Savings to Railways:-
      • Due to improved wagon turn-round (saving of 6 rakes) :
      Rs. 36 lakhs/day
      • Due to improved engine turn-round (saving of 3 MUs) :
      Rs. 12 lakhs/day
      • Due to loading of one extra wagon per rake:
      Rs 4 lakhs/day
      Rs. 52 lakhs/day
    • Savings to Customer (TATA Steel):

      With push-pull, customer shall be able to load rakes within stipulated 3 hours and unload within 2 hours without any penalty being imposed in terms of demurrage.  The entire system of having engines at loading/unloading ends with crew, shunting staff etc. is dispensed with, resulting in substantial savings to Customer.  More importantly, with seamless operation and least probability of bunching, Customer has assured supply of material with fair degree of reliability in forecasts.

Further  improvements:

      • With GPS based loco-troll, under trials, the turn-round will further improve.
      • Synchronization of maintenance schedule of wagons and engines will lead to realization of the concept of train-set and yield benefits in terms of still better utilization of assets (5 Push-pull rakes issued with safety certificate validity of 45 days or 13500 km, are under trial).

Push-pull freight train is best suited for closed-circuit movement with side or bottom discharge wagons.  But it can also be used in other circuits which use Tipplers to unload BOX wagons, subject to the following:

      • Rotary coupling of wagons to avoid uncoupling during Tippling.
      • Modification in Tippler to enable electric engine to pass over.

It is suitable for manual loading/unloading points which have single entry and thus require placement by pushing.

Conclusion:

Push-pull freight train operation is a win-win proposition for both Railways and the Customer. Successful introduction of push-pull freight train operation on CKP division of S.E.Railway has shown that it is possible to bring up to 30% improvements in turn-round of rakes coupled with increase in loading per rake with almost Zero investment by the Railways.  On the whole, it is a milestone in train operations and needs to be emulated elsewhere over Indian Railways involving close-circuit movement of freight rakes.

—-With inputs from SrDOM Manoj Kumar, SrDME Ajit Singh, SrDEE SD Sharma

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There Are 6 Comments

  1. EOS Gold Eu says:

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  2. Vijay Aravamudhan says:

    Dear Rajiv Sir,
    This is simply fantastic move. very interesting indeed and very novel move. I am really proud that Central Railway has now got such an awesome person as Chief Electrical Engineer. Welcome to CR, Sir and All the very best to you for the new assignment.

  3. JAYDEEP BANERJEE says:

    Very well explained the concept of push pull trains. Thanks.

  4. JAYDEEP BANERJEE says:

    (Source Wikipedia) Distributed power / Locotrol

    Advantages and disadvantages[edit]
    The greatest benefit of Distributed Power—and the reason for development of the original concept—is the reduction of drawgear draft forces, permitting the doubling in the size of trains without exceeding draw-gear strength, through the use of mid- or rear-train locomotives.[2] There are also potential train handling benefits; over an undulating track profile, a skillful engineer can manipulate the relative power outputs (as well as dynamic and air brake applications) to minimize run-in and run-out of coupler slack throughout the train.”[3]

    Reduced draft forces along a train will reduce the lateral force between wheel and rail on curves, thus reducing fuel consumption and wear on various running-gear components as well as the potential for a ‘stringline’ derailment.

    Another benefit is quicker application of standard air brakes. With all braking control at the front on a conventional train, it can take several seconds for brake-pipe pressure changes initiated by the engineer to propagate to the rear. Under radio-controlled distributed power operation, the brakes are set at remote locomotives simultaneously with the command initiated on the lead locomotive, providing a more uniform air brake response throughout the train.

    The main disadvantage is the operational time needed, and track configuration required, to add and remove additional locomotive consists. Secondary disadvantages are the costs associated with equipping locomotives with the extra control apparatus and the potential for the intermittent loss of the telemetry signal. This latter is known as ‘Communication Interrupt’ and is coped-with by fail-safe software controls.

    • Mahesh Kumar Jain says:

      you are right and there is no dispute. The distributed power is very common in passenger train and called train sets, emu or memu. Push-pull is the similar arrangement for freight train. Alternatively, synchronised control of the middle locomotive is used were two trains are joined. The leading locomotive controls the middle or trailing or both for trains of 1.5 km or more and when the load is 6000 MT or more. The control means control means control of traction in all the locomotive depending on whether it requires traction or braking on account of gradient of that location and similarly for braking. Such arrangement are used in heavy haul trains like Canada, Australia, South Africa.

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