A 1:6 scale model of a Sentinel steam bus shown at a Midlands Exhibition by A Briggs.

The Sentinel 'Super' model from 1923 was assembled in a radical new plant at Shrewsbury, with a flow line production based on Henry Ford's Model T factory at Highland Park, Michigan, with 1,550 vehicles produced, including buses. Derivatives were also made by Clayton Wagons of Lincoln.

When Sentinel launched a new and advanced steamer, the S type, it had a single-acting four-cylinder underfloor engine with longitudinal crankshaft and an overhead worm-drive axle. Their Sentinel Waggon Works' design of 1935 led to the production of 3,750 Sentinel 'Standards' in the 17 years that followed, the biggest selling steam lorry ever. It was lighter and featured a modernized driver's cab with a set-back boiler and was available in four, six and eight-wheel form, designated S4, S6 and S8. In spite of its sophisticated design, however, it could not compete with contemporary diesel trucks for all-round convenience and payload capacity, and was phased out in the late 1930s.