At the start and the end of its life it built its own products, for the rest of the time it sold vehicles manufactured by sub-contractors.
In 1931, Drewry had a very successful demonstration of its new petrol engined railcar (made by English Electric) on the 7 mile line from Preston to Longridge.
In 1933, the London, Midland and Scottish Railway (LMS) announced that it was to hold an extensive trial of heavy oil locomotives for shunting duties, and among the contenders was a Drewry shunter built by the English Electric company.
It was delivered in spring 1934, and after operating in Salford goods yard it was sent on loan to the War Department in 1940, and they purchased it in 1943.
It continued to rely on contracting out the manufacture, using companies such as Vulcan Foundry and Robert Stephenson & Hawthorns.
In 1962, Drewry acquired a controlling interest in E E Baguley Ltd, and formed Baguley-Drewry Ltd, thus once again building its own locomotives, in Burton upon Trent.