Railroads, trains, and locomotives

The language used in discussing the method of using a powerful, self-propelled vehicle to pull one or more passive wheeled vehicles along a special roadway in which flanged wheels travel on a pair of equidistant supports tells a lot about the history of this important mode of transportation. There is no really satisfactory overall word to describe this means as a whole, as say automobile is sufficient for a personal transport system based on self-propelled vehicles. Instead, we say railroad or railway (really just the supports), locomotive (the self-propelled puller), or train (the line of vehicles being pulled). This correctly suggests that the components of what we shall call a railroad (using the support system for the whole) arose separately.

The support system gets the credit because it really was the first to arrive on the scene. Planked roads in and out of mines go back very far in history and had evolved into rails as early as 1556; we know this from an illustration in Agricola's book on mining. Two hundred years later, when iron began to be plentiful, wooden rails started to be covered with iron flanges to reduce wear.

Although one can assume that initially single vehicles were used on the first railways, miners learned that it was more efficient to use several vehicles linked together, pulled by mules, oxen, donkeys, or horses in different mines. Thus the railway came to be associated with the train of vehicles used on it. In the early 19th century, such railways had gone beyond the mines and were being used to haul goods to canals. In England more than 20 such rail lines, with trains pulled by animals, had been authorized early in the 19th century.

Steam engines large enough to pull themselves -- locomotives -- or themselves and a train were too heavy for dirt or even gravel or paved roads, although some that were tried on roads were no heavier than modern sports utility vehicles. Furthermore, the earliest steam engines were associated with mines, where people were used to railways. So the combination that we know as the railroad system was fixed early in the 19th century: a locomotive on rails pulling a train.

Such locomotives were the first vehicles in which turning wheels supplied the power to move forward. In all previous vehicles, humans or other animals moved forward by walking or running, and the wheels were used mainly to reduce friction with the roadway.

At the beginning of the 19th century, people did not believe that a machine could be built that was strong enough to move itself and any significant load as well. Railroad pioneer Richard Trevithick won a significant bet of 500 guineas by pulling ten tons of iron and more than 70 passengers a distance of 14.5 km (9 mi) in southern Wales. When the engine arrived at the mine, it was left there to power stationary machinery.

Even after Trevithick's demonstration, it was generally believed in England that a locomotive could only pull loads on level rails. No early English railroad lines ran up hills -- instead, they went around them or cut through them (which, along with cuts for canals, greatly improved the study of geology).