OREANDA-NEWS. In yet another technological improvement and upgradation, Indian Railways has now decided to install a new fuel saving device called Auxiliary Power Unit (APU) in Diesel Locomotives which will result in saving of more than Rs 20 lakh per locomotive annually. 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.

 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.

 APU is a self-contained unit containing a small diesel engine coupled to a compressor and alternator for battery charging. It has its own set of controls, accessories and is integrated to the existing microprocessor control system of locomotive.