Puffing Billy Locomotive



My research into my latest project has led me to some interesting tales.


In 1802 Richard Trevithick built a road locomotive using high pressure steam, the exhaust from the cylinders was so loud that he had to find a way to silence it. His idea was to direct the exhaust  into the smoke box, he observed that the fire was now burning much brighter in the fire box, however he failed to carry out any further research, so credit for the blast pipe was awarded to another engineer of the period.


Richard Trevithick then turned his attention to a rail locomotive and on the 13th of February 1804, at Pen-y-Darren iron works his locomotive hauled a load of 15 tons at a speed of 5mph, to the Merthyr- Cardiff canal. The biggest problem he found was slipping. This problem was partially solved by Christopher Blenkinsop who in 1811 built a locomotive for the Middleton coal mine.  He used cogged wheels engaged in a rack at the side of the track. It was William Hedley ably assisted by the young Timothy Hackworth, blacksmith at Wylam coal mine in 1812,  that finally solved the problem with Puffing Billy, they used two sets of gears driven off a crankshaft to turn two sets of wheels.


Puffing Billy’s water tank


The full size water tank was made up from wrought iron plates 2 foot wide by 6 to 8 foot long.  In 1810 this would have been the limit of rolling. It can see from the drawing that the tank sides are joggled to obtain the size needed for the tank. The plates would have been returned to the rolling mill to have the joggle rolled into the edge, holes would then be drilled or punched into the edges and the two halve’s riveted together. The angle plates would  also have been rolled out in the mill.

On certain day’s visitors to the Ironbridge Industrial Museum can see good examples of their work.  A phone call to the museum is recommended to establish which days they are working.

We now return to the model. To produce the tender tank it was necessary to make up some sort of former. In the photo’s you will see the male and female formers used to reproduce the joggle in the plates. I then machined a step 0.040 deep for the length of tank sides and 0.187 wide  the angle was then machined to complete the form, four holes were drilled and tapped for the stop bar at the front of the former for the tank sides to sit against, before the plates are pressed, it will be necessary to anneal the brass plates, care must taken here half hard brass sheet will greatly reduce the distortion caused in the manufacturing process.