Gas Tracks

Buses and autorickshaws run on it. Soon Indian Railways will roll out its engines on CNG

After taking over the roads, the CNG is changing tracks. Indian Railways is well on course to start running its Diesel-Electric Multiple Unit (DEMU) engines on diesel mixed with Compressed Natural Gas (CNG). The results of a year-long pilot study at Delhi’s Shakurbasti Diesel Shed have shown a 50 per cent reduction in consumption of diesel when it is mixed with CNG.

Engineers at Northern Railway are an excited lot. ‘‘The results have far exceeded our expectations. We have tested this dual fuel on a DEMU engine plying on suburban routes like Delhi-Rewari, Delhi-Rohtak and Delhi-Shamli and there have been no complaints. On the contrary, after mixing it with CNG, the consumption of diesel came down to 40 litres per hour from the earlier 80 litres per hour,’’ says an engineer involved with the project. Northern Railway now plans to run eight more DEMU engines on dual fuel by year-end.

A special kit has been designed for the project by Cummins. ‘‘It has a 40 cylinder casket which can store 600 kg of CNG at a time. Once the CNG is taken to the engine room, it mixes with fresh air and is inducted into the engine alongwith diesel. With CNG’s ignition temperature being high, it is the diesel which burns first. It is only after the engine reaches a certain speed that CNG takes over,’’ says the engineer. The project was cleared by the Ministry of Railway’s Research Design and Standards Organisation (RDSO).

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But would this experiment leave some side-effects on the health of the engine? Engineers are quick to point out that the special kit has a Programmable Logical Control which monitors parameters like RPM, knock and exhaust gas temperature inside the engine and decides on the CNG substitution. ‘‘This prevents any harmful effects on the engine,’’ said Northern Railway’s Deputy Chief Mechanical Engineer (Diesel) Sandeep Jain. ‘‘Also, the kit may cost a steep Rs 41 lakh as of now but would recover its cost in less than two years by leading to a fuel-saving of Rs 27 lakh annually,’’ he adds.

That the Shakurbasti Diesel Shed gets a regular supply of CNG has been ensured with the Indra Prastha Gas Ltd laying down a dedicated CNG pipeline right upto the shed.