Is economics is the only reason to prefer electric traction over diesel traction? Certainly not.
Horse Power of Locomotive
Horse power of locomotive is determined by the power generated by Diesel Engine in case of Diesel Locomotive whereas capacity of transformer for Electric Locomotive. Increasing transformer capacity had never been a problem maximum capacity of 10000 HP can be produced by 6 axle locomotive. Advantage with high horse power is the extra speed at which full load can be hauled. For this reason, the average speed of electric traction is 27 Kmph as compared to 23.5 for diesel traction for the year 2011-12 as per Annual Statistical Statement.
Average Load per train
The Hauling capacity of Electric Locomotive is 3102 for electric traction as compared to 2992 for diesel traction. The same situation prevails for coaching train requiring two locomotive for hauling 24 coach. Picture below shows 12628 Karnatka Express at Manmad Station. Electrification from Manmad towards Daund is under progress.
Regeneration during braking
It is possible to regenerate power during braking which is fed back to the utility or consumed by another train in the section. This makes the electric traction much more attractive for frequent stopping trains and train operation in undulated sections. In diesel traction also, regeneration can be used partially to meet auxiliary load and head on generation but no scheme has been put into use so far. Regeneration figures in electric traction varies from service to service. It is in the range of 30% and 15% for sub-urban and freight/coaching services respectively.
Regeneration reduces wear and tear of brake blocks, brake rigging thus reducing maintenance cost. How much is the impact on maintenance cost or reduction in the consumption of brake block has never been studied. Regeneration in sub-urban is to the extent of 30%, and immediate reduction in consumption of brake block was felt.
HSD oil is subsidized considering its implication on truck movement having implication for price index but it is otherwise for Electric unit cost. The unit cost for agriculture/household is subsidized at the cost of Electric Traction. Average cost of HSD oil during 2010-11 was Rs. 37.72. The price has gone up with subsidy element being taken away slowly as shown in the table below
|Date||Cost of HSD Rs/litre|
|Oct 01, 2013||52.54|
|June 01, 2013||50.25|
|September 14, 2012||46.95|
|October 01, 2011||40.91|
|Nov 2, 2010||37.75|
It is only due to electrification with 65% of freight and 50% of passenger traffic on electric traction that Indian Railways could sustain the pressure of rising fuel bill.
Electric Traction is right step towards sustainable development. It creates infrastructure to facilitate running of trains on Electric Traction without differentiating the source of power generation which can be renewable or non-renewable source of energy. The day is not far when percentage contribution of hydro, nuclear, solar and wind power generation will keep on increasing. Rail transport with electrification will make the best use of renewable source of energy instead using crude oil.
From the figures of Line Haul Cost, it is quite visible that the maintenance cost of diesel locomotive is much higher as compared with electric locomotive This is also evident from the fact that conversion of chemical energy into electric energy will certainly be energy intensive as compared to conversion of HT electric energy in to LT energy.
Noise and Atmosphere pollution
Power generation by burning of diesel oil at the place of usage will generate noise and atmospheric pollutants such as nitrogen and sulfurous gases. There are about 50 locos at NDLS station during morning and evening hours. Imagine the situation of atmospheric noise and air pollution at NDLS station if there would not have the electrification.
There is hardly any disadvantage with electric traction may be one, that is train getting stranded in case of power supply failure either through grid or breakdown. But how many such cases per year? Sum total of loco and traction failure is less as compared to diesel loco failure mainly because power is generated at source in every unit thus adding unreliability.
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