Indian Railways has decided to install an Auxiliary Power Units in all its Diesel locomotives which would allow it to save Diesel worth Rs 20 Lakhs per Engine. With an approximate number of 5000 Engines in Operation, this technology would allow Railways to save Rs 1000 Crores annually.
Due to a large number of trains, moving on limited track, some trains have to wait for path or for giving precedence to other trains. Locomotives of these trains remain in idle condition because of the requirement to provide compressed air for train brake which is supplied by compressor driven by engine and to charge the locomotive battery. In order to save fuel during idling, Indian railways are providing a system called Auxiliary Power Unit (APU) in Diesel Locomotives.
In APU System main Engine shuts down and small 25 HP Engine starts, and charges batteries and air brake pipes, when loco idles for more than 10 minutes. The diesel engine of APU consumes only three litres of diesel per hour in comparison to 25 litres by the main engine. Expected savings per loco fitted with APU is Rs. 20 lakh per year on account of saving in fuel oil only.
To begin with, this device has been installed in twelve existing diesel locomotives through retrofitment. In future, Indian Railways plan to fit APU on 100 per cent in newly built diesel locomotives which will then result in saving of more than Rs. 60 crore annually in future. Use of APU also results in lower CO2 emission and other pollutants like HC, NOx, CO etc.