Sentinel Waggon Works (Shrewsbury)

The Sentinel Waggon Works was a British manufacturer of steam wagons and small industrial locomotives operating from Shrewsbury, Shropshire from 1915 (originally as Alley & MacLellan of Glasgow, founded 1903). The firm specialised in high-pressure vertical-boilered steam wagons and rail vehicles using a chain-driven, valve-gear-free direct system.

For railway customers Sentinel built a range of small industrial 0-4-0 and 0-6-0 vertical-boilered shunters for collieries, factories and works railways, and the Sentinel-Cammell railcars used on lightly-trafficked branch lines (including the LMS, LNER and the Welsh narrow-gauge railways). The Welshpool & Llanfair Light Railway's earlier passenger service was operated for many years by Sentinel railcars.

Sentinel was acquired by Rolls-Royce Diesels in 1957, ending steam vehicle production. The Shrewsbury site is now a residential and industrial estate.