This is a demonstration model of a uniflow steam engine valve introduced in 1908 by Johann Stumpf of Germany. The model was constructed by Severn-Lamb Ltd. of Stratford-upon-Avon, England.

Beneath the hood, the Jeep is home to a 100ci V4 trunk-piston, poppet-valve uniflow steam engine from the 1960’s. It only produces between 130 hp and 140 hp, but churns out a remarkable 2,500 lb ...

They were assisted in manoeuvring by uniflow steam cylinders, the steam being supplied by a waste-heat boiler operating on the gas engine exhausts.