Improving Railways

Source: The Hitavada      Date: 13 Sep 2017 12:09:16

By R. N. Malhotra

The merit of pairing a locomotive in order to provide one at each end of the train is now an operational and safety imperative and the only decision directly impacting actual train running and relieving the stress on lines.

While the Indian Railways (IR) struggles to retain relevance in tomorrow’s economy, frequent accidents on the railway network have exposed that it is operating under severe stress. This has led to a situation where the needs of punctual running can no longer be balanced with need to carry out critical, safety related maintenance activities, which require the stopping of train movement. Most of the maintenance activities need physical stoppage of trains, with the period for this being called a traffic block. The Railways has reached a stage where the physical time available is not commensurate with required maintenance in several locations. This is the case on several of the routes. This has led to the adoption of expedient processes under duress and a general sense of exasperation.

Given that laying of new tracks is an expensive and long term proposition, what can be done to accommodate more trains? Conventionally, the issue was tackled by signalling innovations, investing more in awareness and grading the speeds of trains which follow each other. This brought in the four aspect signalling, automatic signalling. However, there is a limit to how much innovations can help and that limit has also been exhausted at several high traffic density routes.

Fundamentally, we can tackle the issue in the good old way — clearing the sections faster so that either more trains can be accommodated or the track is available for maintenance for a longer time. This calls for more motive power and that has been the key justification for inducting more powerful locomotives.

Historically, multiple locomotives have been concatenated to give more tractive power. This solution causes the couplings closer to the locomotives getting stressed more and being vulnerable to breaks, which can eventually result in parting of the train. This limits the number of locomotives that can be joined together. In India, this is limited to two for higher power electric locomotives and up to three for lower power electric locomotives.

The ideal solution is to haul the load with locomotives interspersed in the train, which reduces the coupler forces and also permits more effective and efficient braking. Here, the challenge is of having a remote control which can link up all these locomotives and permit operation by crew in the lead locomotive.

Before the induction of what are known as three-phase locomotives, India had a fleet of 5,000 horse power (hp) locomotives, referred to as conventional locomotives. These suffered from lack of regenerative braking ability. Regeneration is the process where the train is braked electrically and the locomotive is made to act as an electricity generator, feeding power to the overhead conductors.

This brings down the energy consumption. However, this advantage accrues from frequent need of braking. Once speed restrictions and differential speed between trains is reduced, this advantage would be mitigated to some extent. The conventional locomotives have several wearing components too, which handle electrical power, necessitating periodic maintenance.

A 5,000 hp conventional locomotive typically costs Rs. 7.5 crore and a 6,000 hp, three-phase, regeneration-capable, locomotive costs about Rs. 15 crore. Recently, IR has awarded the contract for procuring 12,000 hp locomotives from Greenfield factory at Madhepura, Bihar, which would cost about Rs. 28-30 crore, each. The 12,000 hp locomotive essentially has two back-to-back units of 6,000 hp permanently coupled. A 12,000 hp back-to-back unit also would suffer from the issue of high coupler forces near the locomotive. If we can somehow pair a 6,000 hp, three-phase locomotive, with a 5,000 hp conventional locomotive, we would get a 11,000 hp formation but at about Rs. 22-23 crore. By intelligently pairing the three-phase and conventional locomotive, one can retain the regenerative capability of the ‘train’ and save Rs. 6-8 crore in up front capital expenditure.

This brings forth a very interesting proposition. We no longer would see a locomotive in isolation. We can see each 6,000 hp locomotive paired with a 5,000 hp locomotive always at each end of the load forming a motive power combo. These locomotives at the two ends of the train can dramatically reduce the coupler forces and the brake application and release times.

Five thousand locomotives present an investment opportunity of nearly Rs. 67,000 crore which can be spread over the period of their manufacture.

This money would readily pay for itself as substantial capacity would be released to accommodate more maintenance blocks and possibly more trains. Though the existing designs can be put into manufacture, such a plan can also factor in strong redesign after a few years, without impacting the initial deliveries. These 5,000 locomotives would have their own maintenance needs. One can consider creating one facility for 250 locomotives which translates to 20 locomotive sheds, each needing certain manpower. Innovative financing and contracting models can be thought of to create these.

The first expected reaction would be aversion to the use of old technology locomotives. This can be readily answered based on theirperformance and the fact that each class of locomotive has big room for improvement. Conventional locomotives are made up of readily available material and are extremely simple to make and maintain. Being electric locomotives, they do not suffer from any tail pipe emission issue.

The Ministry took the decision to discontinue manufacturing of conventional locomotives, but that decision may need to be revisited. The drawback of not being able to regenerate gets mitigated as one locomotive in each train can regenerate. Also, the conventional locomotive can be selectively fired whenever operational need arises (for example one would not need it while cruising). New control techniques can even mitigate issues like lower power factor of conventional locomotives.

This brings us to the final likely concern. Where is the control to manage two locomotives at each end of the train with one set of crew? This issue is now the coca cola problem - the issue is now just of packaging an available solution which has higher end specifications.

The merit of pairing a locomotive in order to provide one at each end of the train is now an operational and safety imperative and the only decision directly impacting actual train running and relieving the stress on lines. The time for this idea has come. While relieving the stress on the network, this would create high volume of high value employment in manufacturing, and in services, of locomotives.