What Are Railway Locomotives?

History

• Steam locomotives originated in early nineteenth-century Britain. Initially, they were used primarily to transport cargo trains. From 1830 onward, however, commercial passenger transport began to spread. The nineteenth century saw the construction of passenger and cargo railways across Europe and North America, with a corresponding demand for locomotives. The oldest locomotive now in existence, "Puffing Billy," was built in 1813 in northern England to haul coal cars. It is now on display in the Science Museum in London. Another important locomotive from this period was the "Rocket," built in 1829 by Robert Stephenson. The design of this locomotive influenced generations of steam engines, which used similar boilers and arrangements of wheels.
  
  

Design

• Railway locomotives were originally powered by steam engines. In a steam engine, water is heated, usually by burning coal. The resultant steam then enters a cylinder, which moves a piston, which turns the wheels of the locomotive. In the second half of the twentieth century, steam engines began to be replaced by diesel engines, which were less expensive to operate. Railway locomotives in urban areas often run on electric motors which draw power from an external source such as an overhead wire or an electrified third rail on the track.
  
  

Use of Locomotives

• Historically, a single locomotive was used to pull a long train of cars. Many railways now use a "push-pull" system. In this arrangement, the train has a locomotive at either end, one pulling and one pushing. The rear locomotive is remotely controlled, either from the front locomotive or from a separate control car. Push-pull systems allow the train to reverse direction without uncoupling the locomotive simply by changing which locomotive pushes and which pulls. This saves time at rail terminuses.
  
  

Locomotive Heritage

• Historically, railway locomotives were designed and manufactured for practical purposes and were replaced with new versions as improvements were made. Today, however, historians and enthusiasts consider older locomotives worthy of preservation, both as parts of society's industrial heritage and as objects of aesthetic value in their own right. Locomotive enthusiasts gather technical data on older trains, seeking out original documents and parts. Small "heritage railways" offer rides on vintage trains, while museums collect and preserve railway locomotives.