IT may not have the romance and glamour of steam, but this month, diesel is 50 years old.

The National Railway Museum’s (NRM) weekend commemorating the 50th anniversary of the wide-scale dieselisation of Britain’s railway network will begin with a mass start-up of the diesel engines, which are known to their fans as growlers or tractors.

As the age of steam came to an end, new diesel-powered locomotives were needed that were equally at home hauling heavy goods trains as they were on passenger services.

Class 37 was English Electric’s response, and more than 300 of them were built in the late Fifties and early Sixties.

This massive order was split between English Electric’s Vulcan Foundry on Merseyside and Robert Stephenson and Hawthorn’s at Darlington.

The first of these Class 37 engines to roll off the production line in 1960 was D6700, which will be the star of the NRM weekend in York because it has just been restored.

Wearing “BR green”, it entered service in British Rail’s Eastern region.

Steam ended on Britain’s main line in 1968 and in the Seventies, diesel-electric reigned supreme.

In 1974, D6700 was given a new look with a repaint into the standard British Rail corporate blue colour. It was also given a new number, 37 119, and remained mainly in the North and North-East.

The D6700 and the other Class 37 diesels became the mainstay of the British Rail fleet right through to the late Eighties, when D6700 was moved to south Wales, where it worked on secondary passenger trains and fast goods trains.

In the Nineties, the Class 37s were displaced from most passenger work by higherpowered locomotives, but they still hauled passengers in the summer and on secondary services in Scotland and Wales.

D6700, as the first of its kind, enjoyed a certain celebrity status, and in 1998 its owner, EWS, painted it in its original British Railways green and presented it to the NRM, where it was given the name “National Railway Museum”.

At the beginning of the millennium, Class 37s were still in regular use on the main line, particularly in Wales, despite many of them being nearly half a century old. Indeed, they can still be found pulling charter trains for West Coast Railways.

In the past decade, D6700’s celebrity status has grown as heritage railways, including the North Yorkshire Moors Railway, have booked it as a guest engine.

For the past year, it has been undergoing bodywork and other repairs in the museum’s workshop in preparation for its anniversary weekend on Saturday and Sunday.

The free event will open at 10.30am on Saturday with a rumbling mass start-up of Class 37s.

Despite its dirty reputation, particularly in comparison with the rosy-tinted way in which steam is viewed, the birth of diesels is extremely significant in the history of the railways.

For nearly four decades, this hardworking locomotive has hauled services all over the UK.

Now in its 50th year, it has been restored for future generations to enjoy as a symbol of the spirit of change in the Swinging Sixties.