Despite the global shift toward clean energy sources, including in the rail transport sector, India is still expanding and continuing to build diesel electric locomotives. This is due to the following factors:

1. Constraints of Infrastructure:
Restructuring the rail tracks for the purpose of electrifying them is highly investment and time intensive. There is a considerable network of railway lines in India and especially in regions that are difficult and mountainous.
2. Economical Inducements:
Diesel engines are adaptable and efficient and can easily operate on non-electrified lines without power.
The costs involved in acquiring diesel engines and their servicing and repairs are lower than those of electric engines both in the initial costs and over the life of the systems.
3. Technological Limitations:
Electric locomotives are effective, however there is a need for a continuous power supply. Power shortage and power grid problems may affect their efficiency.
4. Indigenous Technology:
The country has established a home-grown technology which manufactures diesel locomotives in order to minimize the level of imports.

5. Gradual Transition:
In India, starting with electric locos, there is a very slow expansion.
Utilization of both diesel and electric locomotive makes it conducive to transition.

Even if diesel locomotives have a few advantages, the use of petroleum cannot be overlooked, hence India has to move ahead with electric locomotive enhancement and with other fuels such as hydrogen and bio-fuels.