'Wagon' Boiler, 19th Century

model, scale 1:12, of a 20 hp wagon boiler, 1801-1840.

The 'wagon' boiler, so-called because of its similarity in shape to a covered horse-drawn wagon, was widely used to provide steam at low pressures to early engines. The boiler itself was made from wrought iron plates riveted together, and surrounded by a brick setting, which supported it and allowed for the provision of flues around the outside of the boiler, to maximise the heating area and thus the amount of heat conveyed to water within. The boiler design remained in use for as long as engines operating on low steam pressures survived. However, from the mid-nineteenth century it was supplemented and replaced by new designs such as the Lancashire boiler.