 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 who patented their design in 1873.The distinctive Robey design was an undertype with one or two cylinders mounted beneath a locomotive boiler.The cylinders were mounted beneath the smokebox and a transverse crankshaft ran crossways beneath the boiler, just ahead of the firebox.