The Sentinel Company (the exact title varied over the years) started in Glasgow but established at Shrewsbury in the early years of the 20th Century. Although best known for their steam road vehicles, they entered the rail market by the 1920s for both shunting locomotives and railcars - both products being sold in numbers to the LMS and LNER as well as industry and overseas. When legislation began to limit the use of steam waggons, they developed their own diesel engines and built lorries and buses. This technology attracted Rolls-Royce, whose diesel engine range needed a new manufacturing base, and Sentinel (Shrewsbury) Ltd was bought in 1956. Within 12 months Rolls' ceased steam loco work, but thanks to the sales agreement in place between Sentinel and Thomas Hill, developed a diesel loco based on Sentinel rail chassis and the Rolls C-range (6 and 8 cylinder in line) engines, that won a Capital Goods Design Award in 1964.
Loco production ceased in 1971 after the infamous Rolls-Royce financial "crash". (Sentinels 100hp 9629 and 200hp 4wDH 10003 are in the National Collection.)