Building Trevithick’s second loco - Part one

Designed by Julius de Waal

Some time ago, Julius de Waal described this locomotive on MEWS in 10” gauge, designed as a basis for others to produce working versions in various scales. Many people were interested and asked Julius to produce more details than originally given, and to adapt the design for 5” gauge.

Potential builders must remember that this is a very early design, and all the more fascinating for that. In 5” gauge it should demonstrate clearly how it worked, although it will not be a club track passenger hauler.  However, the geared drive and novel cylinder arrangement will make a great exercise. The boiler is simple compared with later ones, with the interest of the firebox and chimney being at the same end. It is thought that builders will want take boiler testers on board before construction begins to ensure that all will be well, and to settle on a reasonable operating pressure. Builders might also wish to replace some of the brass boiler parts with other materials if the model is to be steamed regularly, although it is expected that steaming of most completed models will be limited to occasional demonstrations.

With increasing interest in making models of locos and other engines from the earliest days of steam this second ever steam locomotive should create plenty of interest.

Trevithick’s first steam locomotive design was for a model which he made in 1797. It was in  February 1804, he produced the world's first steam engine to run successfully on rails. The locomotive, with its single vertical cylinder, 8 foot flywheel and long piston-rod, managed to haul ten tons of iron, 70 passengers and five wagons from the ironworks at Pen-y-darren to the Merthyr-Cardiff Canal. During the nine mile journey the Pen-y-darren locomotive reached speeds of up to five miles an hour. Trevithick's locomotive employed the important principle of turning the exhaust steam up the chimney, so producing a draft which drew the hot gases from the fire more powerfully through the boiler. Steam was at high pressure.

The Pen-y-darren locomotive only made three journeys. Each time the seven-ton engine broke the cast iron rails. The iron works came to the conclusion that Trevithick's invention was unlikely to reduce transport costs and decided to abandon the project.

The second engine (the subject of our model) was designed at 4.5tons to be lighter than the Pen-y-darren locomotive in an attempt to avoid the problem with broken rails.

The 1805 loco was built to run on 5 foot gauge tracks. However, it was the track that was also the downfall of this locomotive, which was built for the Wylam Colliery on Tyneside. Laid in 1748, the wooden track was laid for horse drawn wagons, but the Trevithick locomotive was too heavy for the wooden wagonway. Significantly, George Stephenson was impressed with the trials.

In 1808, Trevithick exhibited his third locomotive in London behind a tall fence with an admission fee of five shillings for a ride. It weighed 8 tons and pulled an open coach on a circular track at up to 12 mph. He described the engine as a “racing steam horse” called Catch-me-who-can.

Unfortunately, the engine ran off the tracks and overturned. As there had been few visitors the event was abandoned. Disheartened, Trevithick gave up steam work and turned to mining and tunnelling. He went to install water pumps in the silver mines in Peru, a post that came to an end after the revolution for independence led by Simon Bolivar. Robert Stephenson, who meanwhile had done rather well with steam locomotives, found Trevithick there, destitute, and helped him to return to England where he died in poverty in 1833.

Click on drawings to download.

SEE PART TWO HERE