Locomotive Basics For Model Railroading
By Larry Truett

A powered locomotive is what makes any train move. Locomotives are often also referred to as engines. A locomotive will usually be placed at the front of the train, and will pull the non-powered cars behind it. Locomotives are usually engineered to run in either direction, but are often designed to face in one direction. Powered locomotives are typically the most expensive rolling stock for the model train enthusiast to purchase, often costing several times that of any non-powered car. Real world railroad locomotives they are modeled on are typically powered by coal, diesel fuel, or electricity. However, the models themselves are typically powered by electric current that flows through the metal train track.

Coal powered "steam engines" were the first locomotives widely used, starting in the early 1800s. Steam engines are suitable for either passenger or freight trains. Steam engines have such a classic look that they still quite popular with model railroading enthusiasts, despite having been phased out of most real world railroading many years ago. Steam engines are powered by burning coal, wood, or other combustibles in a "firebox", which boils water in a "boiler", and then produces the steam that makes these engines move. Steam engines are the ones with the prominent smokestacks, which on some model trains will actually produce smoke.

A typical steam engine will be mostly black with some shiny metal trim, a railroad logo, and a number on the front. There may also be a metal wedge or "cow catcher" mounted on the front of the engine down by the wheels, which is designed to deflect objects from the path of the train. A steam engine will usually have an area for the crew that is at least partially open. Because of the amount of fuel a steam engine needs, it would often be immediately followed in the train by a tender or coal car, which is a car designated
to solely carry fuel and water for the steam engine. A tender will typically match the appearance of the engine, and so is also typically black with metal trim and a prominent logo.

Diesel engines began to replace steam engines in the mid 1900s. Diesel engines are suitable for either passenger or freight trains. Diesel engines have a sleeker look than steam engines do, often shaped like a long box with a rounded front and top. A steam engine will usually have an area for the crew that is full enclosed. The powerful look of a diesel engine makes it ideal for the model railroader who wants to pull a large number of freight or passenger cars. Typically diesel engines can be combined for even more power, whether in real life or for model railroading. Diesel engines are powered by burning combustible liquid diesel fuel, just as diesel trucks are powered. Smaller diesel engines, often called switchers, are necessary for real rail yard operations, and are also popular in model railroading. These are the engines that will add or remove cars from a train. A switcher is easily identified as it is smaller than a normal engine, and is designed to move and pull cars in either direction.

Electric locomotives started to have widespread usage in the mid to late 1900s. While electric engines can be used for either passenger or freight, they are primarily used in passenger trains. An electric engine will ordinarily rely on electrified train track or overhead electric lines to power it. Because of this, real world electric trains will only run where the infrastructure is in place to accommodate them. A model of and electric locomotive, which is itself electric, will typically receive power through the track - even if the train it is modeled on would receive current through overhead lines. Electric powered locomotives are ideal for almost any passenger train, from local metropolitan mass transport to the high speed and sleek "bullet trains".