R30227 BR, Stanier 5MT 'Black 5' Caprotti, 4-6-0, 44755 - Era 4 (Web Exclusive)

Sir William Stanier designed the ‘Black 5’ class of locomotives in 1934 with the intention of them to have a variety of uses, such as, to be used in mixed traffic, as passenger trains, and for hauling freight. A total of 842 ‘Black 5’ locomotives were built between 1934 and 1951. While each locomotive was built to a standard design, many modifications were made to every locomotive that was outshopped.

Their clockwork performance led them to become a test bed for certain potential innovations with one of the most striking examples being the fitting of Caprotti valve gear to twenty examples. Of these twenty examples, eighteen had a standard Caprotti arrangement and two were fitted with a later type. 

This was not the first time that Walschaerts valve gear had been stripped from a ‘Black 5’ with Stephenson’s valve gear being fitted to No. 44767 a year earlier while under its LMS number, 4767.

Some of the most distinctive features of the Caprotti fitted ‘Black 5’s were the shaft-driven valve gear over the wheels, with large prominent steam pipes descending from the smokebox to enlarged cylinders. The boilers on Caprotti fitted examples were raised and the smokebox was also extended.

No. 44755 entered service in April 1948 and was assigned to the Holbeck shed. Less than a week later, the locomotive was moved to Derby and in a roundabout style, found itself back at Holbeck within two weeks of arrival. The locomotive remained largely unchanged throughout its working life with the largest exception being the fitting of AWS in August 1960. 

The locomotive would go on to be withdrawn from the Stockport shed in the dying days of 1963 after spending a little over two years there and a total mileage of more than 500,000 miles.