In 1906 the Polmadie based Mechanical Engineering firm of Alley and MacLellan established the Sentinel Steam Waggon business and by 1915 the company had grown to such an extent that a subsidiary company, The Sentinel Waggon Works (1920) Ltd, was built on the outskirts of Shrewsbury, the workforce being transferred from Glasgow. In April 1923, the Sentinel Waggon Works unveiled the ‘Super Sentinel’ steam waggon design, based on the earlier ‘Standard Sentinel’ steam waggon that had been in production from 1906, up to 1923. The range launched with Engine No. 5001 which was delivered to A. Brain and Co. of Cardiff. The ‘Super Sentinel’ was offered in two basic sizes that offered four/five ton and six/seven ton load capacities and was available in up to twenty four different body styles, including flat tray, tipper tray, enclosed vans, tanker waggons and even a six-wheeled articulated ‘semi-trailer’ version. Production of the ‘Super Sentinel’ continued until 1932, although an advanced ‘S-Type Sentinel’ design was introduced during 1927, production of which continued in a limited capacity up until 1952. Of almost 8,000 Sentinel Steam Waggons built, over 6,000 were built before 1929.

The agricultural machinery company of Richard Garrett & Sons Ltd was founded by John Garrett in 1778 at the Leiston Works, near Saxmundham in Suffolk. In 1840, under the founder’s grandson, the first portable steam engine was produced by the company and in 1876 the company produced the first of its own traction engine types, having previously produced Aveling engines under licence. Garretts were the first company to introduce flow-line production methods to steam engine assembly, their ‘Long Shop’ at Leiston being the first building to house such an assembly line for the mass production of portable steam engines. The First World War and the Russian Revolution proved disastrous for the company’s fortunes and despite Garretts joining other companies to form the combine known as the Agricultural & General Engineers Ltd, in 1932 went into Receivership in 1932, the business being purchased by Beyer Peacock of Manchester. Engine No. 33486 ‘Queen of Great Britain’ is a 4 nhp, five ton Showmans 4CD Tractor built in 1919 at Leiston Works and was supplied new to the Showmans firm, John Cole of Bristol, powering a chairoplane, before subsequently being sold Browning Brothers. Weighing less than five tons and ideal for light road haulage, the Garrett 4CD tractor was probably the most popular steam tractor of the period.