SOLUTION

Self-contained locomotives

In this type, the locomotives or vehicles themselves have the capability of generating electrical energy for traction purposes. Examples of such types of locomotives are:

Steam electric drive

In steam-electric locomotives, the steam turbine is employed for driving a generator used to feed the electric motors Such types of locomotives are not generally used for traction because of some mechanical difficulties and maintenance problems.

Diesel-electric trains

A few locomotives employing diesel engines coupled to DC generators are used to feed the electric motors producing necessary propelling torque. The diesel engine is a variable high-speed type that feeds the self- or separately excited DC generator The excitation for the generator can be supplied from any auxiliary devices and battery. Generally, this type of traction system is suggested in the areas where coal and steam tractions are not available. 

Petrol-electric traction

This system of traction is used in road vehicles such as heavy lorries and buses. These vehicles are capable of handling overloads. At the same time, this system provides fine and smooth control so that they can run along roads without any jerking.

Battery drives

In this drive, Ihc locomotive consists of batteries used to supply power to DC motors employed for driving the vehicle This type of drive can be preferred for frequently operated services such as local delivery goods traction in industrial works and mines, etc. This is due to the unreliability of the supply source to feed the electric motors.