Locomotives: The Power up Front.
Real railroads went from horse-drawn, to steam, gasoline-powered and electric and finally to the electric and diesel-electric locomotives of today. All of those types of locomotives can be purchased in Large Scale for reasonable prices. You can find locomotives to fit any time period and any mode of railroad that you want to model.
Most of the locomotives sold today are very durable machines. They are made for years of service and have enclosed and sealed motor blocks and drive gears. These mechanisms are waterproof and are designed so that they can be easily serviced and repaired. They are powered by electricity from the track or by battery packs located in the locomotives or trailing cars. Some are powered by steam just like the real thing. They are made from plastic, cast metal or brass. Most are UV protected from the sun by the material from which they are built and the paints that finish them.
Your choice of locomotive can be determined by the setting, time period and function you plan for your railroad. The general kinds of locomotives available include narrow gauge, standard gauge and traction.
Narrow gauge railroads had short, very tight curves in the track and were usually situated in very narrow corridors in mountainous areas. This meant that the locomotives were usually not very wide or very long. Because many narrow gauge railroads had steep grades, most of the locomotives were very powerful and some were geared such as the Shays and Climax locos. The narrow gauge railroads were built and ran in the late nineteenth and early twentieth centuries and included the Denver & Rio Grande, Rio Grande Southern, White Pass & Yukon, East Broad Top, Sandy River & Rangeley Lakes and many more. There were also many privately owned mining and lumbering narrow gauge railroads. Most of the locomotives were steam driven and coal or wood fired. Towards the end of the narrow gauge period, some railroads added small diesels or gasoline powered locomotives.
Standard gauge represents most of the railroads built in the United States and includes some of the names you are probably familiar with such as the New York Central, Pennsylvania, Santa Fe or Southern Pacific. Today's standard gauge railroads include Norfolk Southern, CSX, Burlington Santa Fe, Union Pacific, AMTRAK, Canadian Pacific and Canadian National. The standard gauge locomotives were much larger and were primarily steam powered until the mid-1950's when most railroads converted to diesel electric locomotives. Usually, standard gauge locomotives were either designed for passenger service or freight service, although a few were built or used for both.
In the nineteenth and early twenty centuries, many cities had trolley lines and some of those lines expanded to compete with the steam railroads and ran interurbans between cities. These were all electric powered.
Major producers of Large Scale locomotives include, Accucraft Aristo-Craft, Aster, Bachmann, Hartland Locomotive Works, LGB, Marklin and M.T.H. and USA Trains.
When selecting your locomotives you can decide if you wish to model in narrow gauge, standard gauge or traction. You can then select a purpose, a time period and locale for your railroad. Or you can do like many Large Scalers, just buy the locomotives that appeal to you. Many Garden Railroads have an interesting mix of all kinds of locomotives. So it depends on what you want for your railroad. There is no right or wrong way of selecting the locomotives as long as you have fun in buying and running them on your railroad.