01
What is an Electric multiple Unit?
© Railway Technology
An Electric Multiple Unit is a type of train that does not rely on locomotives. Instead, it uses traction motors that are present underneath one or more carriages. This type of train has power distributed throughout each carriage and isn't powered from one end of the train like a typical locomotive. They can be used as high speed trains or even as commuter trains connecting smaller towns to larger cities. They are quite versatile.
02
How does an Electric Multiple Unit work?
©Power Quality
Electric multiple units do not require a locomotive to haul them as the traction motors are fit underneath multiple bogies (carriages) which allows for even acceleration throughout the entire train. A pantograph collects electricity from the overhead catenary wires or a third rail that is present between the tracks and then this electricity is transferred to the traction transformer. The traction transformer converts voltage from the overhead lines to a lower current that is suitable for the motors. The motors are powered by variable AC current, which enables precise control of the motors and their torque. This allows for precise changing of the speed.
03
Brief history of Electric Multiple Units
©Ben Brooksbank
Initially in the late 1880s, the first electric multiple units were devised in the United Kingdom and the United States of America, they were mainly used for travelling shorter distances in urban and suburban areas of a region. In the start of the 20th Century, electric multiple units expanded into larger cities such as London. After World War 2, they were developed into High speed rail and moving into the 21st century, electric multiple units have spread all over the world as a more comfortable, faster and efficient type of train.