Echoes of the past – 1932 Sentinel Steam ‘Bus

The date? 26th January, 1906. The place? Ormond Beach, Florida, just north of Daytona. Fred Marriott had just smashed the world land speed record, setting a new mark of 127.66 mph, the vehicle he used becoming the first to break the 100 mph barrier. The car he did it in? A Stanley ‘Rocket’ – yes, Fred Marriott used a STEAM-powered vehicle to break the record. It would be three more years before an internal-combustion engined car broke the 100 mile an hour barrier; that would be the Benz No. 1, and at 125.94 mph it was still short of Marriott’s mark. It certainly seemed that, in the early years of the 20th century, steam was going to be the standard power source for road vehicles, particularly heavy road vehicles. The author Rudyard Kipling owned a steam car and wrote about them, too, in his short stories.

Scotland, in the later half of the 19th century, was a hive of activity. Heavy industries like coal mining and iron smelting supported a wealth of engineering concerns, and Scotland was world renowned for its shipbuilding and locomotive design. In 1874, Stephen Alley and John MacLellan joined forces to to found Alley & MacLellan Ltd., a general engineering firm that produced steam valves, steering gear for ships, small steam engines and even pre-fabricated steam ships. A few years later they acquired the rights to the Bibby Steam Wagon, and taking this as a starting point designed their own road-going vehicle for the general haulage trade; this ‘Sentinel’ came as a Model 5, with a ‘tipper’ body or Model 6, a flat bed wagon. Motive power came from an under-mounted 2 cylinder, double-acting steam engine, with poppet valves. Steam was generated in a vertically-mounted boiler, with cross water tubes, and effective superheating (the method whereby flue gases are used to raise the temperature of the steam still further, thereby allowing it to generate even more power). Power varied according to the quality of coal used and the condition of the flue and its liner; good Welsh ‘steam coal’ was prefered.

By 1914, the company felt the need to expand, and it chose a site in Shrewsbury, about 30 miles west of the heavily industrialised West Midlands. In a startling move, the firm fabricated its own modular factory, and moved it to the new site! By now solid rubber tyres had become standard on both their wagons and the optional trailers. The Great War caused a large expansion in demand for military wagons, and this was a boom time for the firm, which in 1918 changed its name to ‘The Sentinel Wagon Works Ltd’. However, a ‘perfect storm’ was coming. The end of the Great War meant a general down-turn in economic activity, and the flood of ex-military petrol-engined wagons onto the civilian market was nearly fatal to the firm. That, along with Goverment discrimination in the form of an ‘axle weight tax’ caused by the Salter Report (steam traction is always heavier than internal combustion), and ‘wetted area’ tax, which struck at the perceived nuisance of steam road locomotives, was a major blow. The company diversified with its first small railway locomotive being built in 1923, and its very last ‘Standard’ wagon being finished in the same year (this venerable design, built from 1905 – 1923, had totalled 3,746 examples!) The first of the superb ‘DG’, or Double Gear, series of vehicles comprising wagons, tipper lorries, and ‘buses was rolled out in 1927, and by 1938, 851 had been built.

The outbreak of the Second World War saw the firm put on a war footing again, but this time there was no demand for steam wagons. Instead, ‘Sentinel’ built no less than 11,000 Universal Carriers (sometimetime known as the Bren Gun Carrier) that small, ubiquitous tracked vehicle used in many forms by the U.K. and Commonwealth forces during WW2 and after. They also repaired thousands of U.S. built automotive engines including those from Buda, Caterpillar and Cummins. Sentinel was aided in this by the fact that they had adopted a Ford-style production line system when they moved the factory to Shrewsbury.

After the war ended, steam traction did too, apart from a final batch of wagons for Patagonia (it is said that the Argentine Government ‘forgot’ to pay for the latter part of the batch!) Sentinel switched to diesel-engine power for its railway locomotives, and was taken over by Rolls-Royce in 1956. By the 1960s the grand old name had faded away.

Imagine my surprise then, when returning to London after a visit to the de Havilland Historic Aircraft Trust at South Mimms, when I overtook a steam vehicle in ‘full flight’! I was on a four-lane highway at the time, and quickly sped ahead until I found a parking spot, and waited. Shortly afterward, this wonderful Sentinel DG4 Steam Passenger Bus hove into view, pounding down the road at about 45 mph. It bore the legend, ‘1932 “Sentinel” Steam Passenger Bus’, SBC No. 1, and the title of ‘Lake District’ on the side. If you look closely, you can see the exhaust from the under-mounted twin-cylinder engine. Registered ‘KG1123’, this DG4P is the sole survivor of its kind, and despite being based in Cumbria, in the North West of England, it is seen at steam gatherings around the country, especially those sponsored by the Sentinel Driver’s Club, such as the large rally at Bedford in 2012.

An anachronism? Who knows; steam traction may yet make a comeback. Until it does, I shall keep an eye out for this handsome reminder of a byegone age – the Sentinel !

One comment on “Echoes of the past – 1932 Sentinel Steam ‘Bus”

  1. An outstanding opportunity which you exploited quite well!


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