Semi-portable engine

They were built in a factory as a single unit including the boiler, so that they could be rapidly installed on site and brought into service.

Although the earliest examples can be dated to Richard Trevithick in around 1800, the type is best known as the products of Robey & Co. of Lincoln[1] who patented their design in 1873.

During factory testing, the engine bed would have to be raised on timber baulks to provide this extra height.

[4] A typical large stationary engine of this time used a number of lancashire boilers, set in brickwork surrounds.

Locomotive boilers though, as used here, had greater capacity and could provide a mechanical plant that could run continuously for long periods.