Early iron rails

In 1767, Ketley ironworks began producing cast iron plates, which were fixed to the top of wooden rails with nails, to provide a more durable running surface. This construct was known as strap-iron rail (or strap rail) and was widely used on pre-steam railways in the United States.[12][13] Although relatively cheap and quick to build, they were unsuited to heavy loads and required ‘excessive maintenance’. Train wheels rolling over the spikes loosened them, allowing the rail to break free and curve upwards sufficiently that a car wheel could get beneath it and force the end of the rail up through the floor of the car, writhing and twisting, endangering passengers. These broken rails became known as “snake heads”.[13]

When wrought iron became available, wrought iron plates provided an even more durable surface. The rails had projecting lugs (or ears) with a hole to enable them to be fixed to the underlying wooden rail.

Iron plateways

Section of L-shaped plate rails

A long fish bellied rail supported over several chairs

An alternative, developed by John Curr of Sheffield, the manager of the Duke of Norfolk‘s colliery there. This had a L-shaped rail, so that the flange was on the rail rather than on the wheel. This was also used by Benjamin Outram of Butterley Ironworks and William Jessop (who became a partner in them in 1790). These were used to transport goods for relatively short distances down to canals, though Curr’s ran between the manor colliery and Sheffield town. These rails are referred to as plates, and the railway is sometimes called a plateway. The term “platelayer” also derives from this origin. In theory, the unflanged wheels could have been used on ordinary highways, but in practice this was probably rarely done, because the wagon wheels were so narrow that they would have dug into the road surface.

The system found wide adoption in Britain. Often, the plates were mounted on stone blocks, and sometimes without sleepers, but that was liable to cause the rails to spread apart, increasing the gauge. Railways of this kind were widely used in south Wales. In particular to transport limestone down to ironworks, and then iron from the ironworks to a canal, sometimes several miles away, to take the products to market. The rails were at first made of cast iron in lengths of typically three feet, spanning between stone blocks.[14]

The stone blocks had been assumed to be permanent, but experience quickly showed that they settled and gradually moved under traffic, creating chaotic track geometry and causing derailments. Another problem was that the running surface was liable to become obstructed by stones, displaced from the ballast. An alternative was to use an iron tie bar to keep the rails to the proper gauge, incorporating a shoe in which the rail was fixed.[14]

An example of this was the Penydarren or Merthyr tramway. This was used by Richard Trevithick to demonstrate a pioneer locomotive in 1804, using one of his high pressure steam engines, but the engine was so heavy that it broke many of the rails.