The history of Sentinel Industrial Locomotives Ltd goes back many years before this company was set up in 1925.
In 1875 the Sentinel Engineering Works at Polmadie in Glasgow was opened by Irishman Stephen Alley and his Scottish partner John Alexander MacLellan. Five years later the company moved to Jessie Street in Glasgow as they had outgrown their Polmadie premises.
In 1903 Alley and MacLellan acquired the business Simpson and Bibby of Horsehay, Shropshire, who had been working in the production of steam road vehicles. This new business was moved to Polmadie.
In 1905 the first Sentinel Steam Waggon was manufactured. The company spelling of waggon rather than wagon being used to indicate that the Sentinel product was superior to other wagon manufacturers. The waggons were steam powered road vehicles with vertical boilers and a chain drive.
In 1905 the waggon manufacturing was moved to a new factory in Shrewsbury alongside the LNWR mainline to Crewe.
In 1917 the company was bought by William Beardmore & Co Ltd.
Following financial problems in 1920 the company was reorganised as Sentinel Waggon Works (1920) Ltd. The Sentinel ‘Super’ model that followed in 1923 was assembled in a radical new plant at Shrewsbury, with a flow line based on Henry Ford’s Model T factory in Michigan USA.
In 1925 the Sentinel Industrial Locomotives Ltd was established as a separate company, with its office in Chester and Arthur Thomson as Assistant General Manager. This activity was merged with that of the Railway Department in Shrewsbury in 1928.
As opposed to the conventional steam locomotive transmission Sentinel locomotives have a boiler feeding steam to a vertical twin piston and cylinder engine arrangement, similar to a car engine but powered by steam, which powers a chain drive to the locomotive’s driving wheels.
Sentinels tended to have large water tanks which extended to almost the full width of the locomotive and the central location kept the weigh distribution between the two sets of wheels which help with the wheel adhesion. Some Sentinel designs were capable of operating for 16 hours on one tank of water because the tank was so large.
The development of petrol powered vehicles meant that by the late 1930s the production of steam powered road vehicles was phased out.
In 1946 Thomas Hill (Rotherham) Ltd signed an agency agreement with Sentinel for repair and maintenance of diesel vehicles. Thomas Hill had been established in 1937 at Whiston and was principally concerned with repair and maintenance of steam road vehicles, and in particular Sentinel steam waggons which were popular in the area.
In 1947 Sentinel offered to extend the agreement for diesel vehicles to include the steam locomotives and an agency was accepted by Thomas Hill for sales and servicing. The company became Sentinel (Shrewsbury) Ltd and had developed a new range of diesel lorries.
In 1958 the last two Sentinel steam locomotives were delivered marking the end of an era. The following years saw the Sentinel site and name only referred to unofficially as several acquisitions by large companies, such as Perkins Engines Ltd, Caterpillar, Lucas, Varity and Doncasters Aerospace replaced the trading name.
Industrial Locomotives Preserved
| Works No | Built | Name | Location |
| 6155 | 1925 | Coalbrookdale Museum of Iron | |
| 6185 | 1925 | Coalbrookdale Museum of Iron | |
| 6515 | 1926 | GWR No 12 Isebrook | Cholsey & Wallingford Railway |
| 6807 | 1928 | Gervase | Elsecar Railway |
| 7109 | 1927 | Joyce | Midsomer Norton Station |
| 7232 | 1927 | Ann | East Lancs Railway |
| 7492 | 1928 | Fry | Avon Valley Railway |
| 8024 | 1929 | Gas Bag No 7 | Ribble Steam Railway |
| 8837 | 1933 | 68153 LNER No 54 | Middleton Railway |
| 9365 | 1945 | Belvedere | Northamptonshire Ironstone Railway Trust |
| 9366 | 1945 | No 11 | Buckinghamshire Railway Centre |
| 9369 | 1946 | Muskateer | Northamptonshire Ironstone Railway Trust |
| 9370 | 1946 | No 1 Neepsend 2 | Great Central Railway |
| 9373 | 1947 | St Monans | Ribble Steam Railway |
| 9376 | 1947 | No 7 | Elsecar Steam Railway |
| 9387 | 1948 | Sandford Station Railway | |
| 9518 | 1951 | 5208 | Buckinghamshire Railway Centre |
| 9535 | 1952 | Foxfield Railway | |
| 9537 | 1952 | Susan No 7 | Barry Tourist Railway |
| 9559 | 1953 | No 4 | Tanfield Railway |
| 9561 | 1953 | John | Bo’ness & Kinneil Railway |
| 9596 | 1955 | George | Mid Norfolk Railway |
| 9599 | 1956 | William | Elsecar Steam Railway |
| 9622 | 1958 | Swansea Vale No 1 | Teifi Valley Railway |
| 9627 | 1957 | Ranald | Bo’ness & Kinneil Railway |
| 9628 | 1953 | Robin | Summerlee Heritage Park |
| 9629 | 1957 | Frank Galbraith | National Railway Museum – Streetlife Museum of Transport at Hull |
| 9631 | 1958 | Denis | Bo’ness & Kinneil Railway |
| 9632 | 1957 | No 5 | Chasewater Railway |
Preserved British Steam Locomotives 