You see the number of people travelling by rail in US, it's much less unlike in India. Railways earn there by freight here in India too it's the same. But in India railways focus is on passenger transportation first then on freight, but whereas there it's only on freight. We can't have that much powerful diesel engine to carry 3km long goods because it will block the line and the goods train can't even stand on the railway station as the railway station will be small. The no of passenger train is way too many, we need trains which can clear the line faster which can be done by electric trains as it is faster than diesel. Secondly we need alternate source to run the trains, diesel is going to get over which is nothing but a refined product of crude, so electric can be of greater boost.