Like them or loathe them, the EMD JT42CWR, better known as the class 66 or, thanks to that peaked roof, Shed has become a ubiquitous feature of the British railway scene, and is set to remain so for years to come. There can be few places on the national network which haven't seen a Shed at some time since their introduction in 1998.

Although built in Canada they originate from the US mid-west, from McCook in the Chicago suburbs, where the Electro-Motive Division of General Motors had their locomotive building plant, and where the prime mover for the 66 is still manufactured. The engine in the 66, a 12N-710-G3B-EC is a linear descendant of the first two stroke diesel developed specifically for rail use by the Winton Engine Company and Electromotive Corporation in 1938, the 567. The two companies, Winton & EMC, had been bought by GM in 1929, they were merged in 1941 to form the Electromotive Division.

The 567 was succeeded by the 645 series in 1966 which in turn was superseded by the 710 in 1984. The numbers incidentally refer to the cubic capacity (in cu inches) of each cylinder. Two stroke technology was adopted by Winton in the early 1930s on the back of research money from the US government into improved submarine engine designs. It offered the promise of greater power for a given weight of engine block than could be obtained from contemporary four stroke engines. Although less fuel efficient than four strokes, EMD have stuck with their two stroke designs now for over 70 years, each succeeding type being more powerful, and more efficient whilst emitting fewer pollutants, than its predecessor. In the North American market EMD had, by 1969, seen off almost all their competitors; Fairbanks-Morse, Baldwin-Lima-Hamilton and Alco. Only GE remained and it is GE which in the past 20 years has overtaken EMD in the locomotive sales stakes. But here, for the moment, and elsewhere in Europe the 66 remains the best selling diesel of recent years, although with the advent of GE's Powerhaul product (aka Ugly Betty) that may change.

GM sold EMD to two private equity groups in 2005, who in June 2010 sold it to Caterpillar Inc. EMD and their predecessors have been in the rail internal combustion engine market almost from the beginning (EMC was originally founded in 1922), I for one hope they survive and prosper in the 21st Century.

Here is a selection of shed pictures, from other galleries on the site for those of you who can't get enough of Britain's Favourite Diesel :-)