Is the working of diesel and electric locomotive same?

Locomotive engines are the most important thing in railways. Normally there are 3 types of locomotives. They are steam, diesel and electric locomotive engines. Diesel and electric engines are mostly used by railways. Without diesel or electric power, engines don’t work. But do you know, the working principle of both the locomotive engines is same?

Welcome to Engineering Master. In this article, we will tell you the answer…


Diesel and electric engines ultimately work with same principle. The only difference is the source of power. Diesel engine generates its own power by burning the fuel and hence self powered and electric locomotive draws its power from outside source. You must saw the pantograph over the electric locomotive. This pantograph helps the locomotive to draw the power from overhead cable.

Both locomotives are run by traction motors. Traction motor is an electric motor which is more powerful and larger than a normal induction motor. Traction motor runs with AC or DC. So it is clear that it both types of locomotives have traction motor and they need electricity to run it.

In diesel engine, an internal combustion engine (IC engine) is there which runs with fuel and produces electricity. This IC engine is known as diesel engine. Diesel engine do not run the traction motor directly. There work is to generate electricity. And this generated electricity is used to run the traction motor and hence the locomotive runs. In this way a diesel engine works.

Electric engine draws the power directly from the overhead cables. But the current in overhead cables is around 25000 volts. This high amount of current is not required to run the electric engine. So the high voltage current is controlled by a transformer. This controlled electric current is used to run the traction motor and hence locomotive runs. In this way an electric engine works.



5 thoughts on “Is the working of diesel and electric locomotive same?”

  1. I have a query ,that why in diesel engine trains the mechanical power generated is in IC engine is not directly use to run the traction motors ,why the mechanical power is first converted to electrical power (with some losses ) and then used to run traction motors ?

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