What is a Locomotive?

Mary McMahon
Mary McMahon

A locomotive is a specialized type of train car which is self-propelled, generating energy through the burning of fuel, the use of electricity, magnetic levitation, or other experimental methods. Locomotives can be used to push or pull train cars, and they can be seen on railroad tracks all over the world, propelling passengers and freight to various locations.

Diesel-electric locomotives provide propulsion for most freight trains in North America.
Diesel-electric locomotives provide propulsion for most freight trains in North America.

As a general rule, a locomotive is extremely powerful, because it must be capable of pulling or pushing a chain of train cars. Unlike locomotives, train cars lack a source of power, and their movement is totally dependent on the locomotive. Locomotives can pull long strings of heavy cars on both flat surfaces and grades, and they are literally the powerhouses for trains.

Steam locomotives were used to move rail cars throughout the 19th Century and for the first half of the 20th Century.
Steam locomotives were used to move rail cars throughout the 19th Century and for the first half of the 20th Century.

The earliest locomotives were developed in the first decade of the 1800s, and they were powered by steam. They were also fairly crude and low powered, although the steam engine was quickly refined during the 1800s to create powerful steam locomotives which could burn wood, coal, and other materials, depending on what was available. The development of the locomotive enabled the construction of railroads, which were a dominant method of land transportation for people and freight well through the first half of the twentieth century.

The traction motors on a diesel electric locomotive can be reversed to facilitate breaking, however a train with a full consist still takes some distance to stop.
The traction motors on a diesel electric locomotive can be reversed to facilitate breaking, however a train with a full consist still takes some distance to stop.

Although the classic image of a locomotive involves placement at the head of the train, a locomotive can also push from behind. Some railroads use what are known as push-pull operations, in which a locomotive pulls a train in one direction, and pushes it in the other. This eliminates the need for time consuming track switching, as the train can move easily in either direction.

Many modern locomotives run on electricity.
Many modern locomotives run on electricity.

Locomotives which are designed to pull freight trains tend to be the most muscular, since freight trains can get very long and extremely heavy. Passenger locomotives are more lightweight. Switchers or shunting locomotives are the smallest and most agile of the locomotive family, being used to move trains and train cars around in train yards. As a general rule, switchers are capable of immense amounts of traction, enabling them to quickly get heavy trains in motion and then using that energy to move them to their end destinations.

Before the electric locomotive, steam-powered trains were a popular form of transportation, especially during the 1800s.
Before the electric locomotive, steam-powered trains were a popular form of transportation, especially during the 1800s.

Several railroads continue to run classic steam locomotives, typically as a novelty. Many others use diesel and other fuels to power their locomotives, while electric locomotives are growing in popularity, along with locomotives which use more experimental technology. Light rail systems used for commuting often use self-powered cars which are known as motor coaches or motor cars; because each car runs under its own power, it is easy to move light rail trains around as needed, adjusting the number of cars and runs to meet demand.

Diesel-electric locomotives were first used in Sweden in 1913.
Diesel-electric locomotives were first used in Sweden in 1913.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments

anon30124

What is the average speed of a locomotive train?

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