A Class 11 0-6-0 diesel shunter owned by the Severn Valley Railway Charitable Trust has returned to operational service after undergoing a major overhaul.

Currently based at Kidderminster on the Severn Valley Railway, Class 11 No. 12099 underwent its major overhaul at the railway’s diesel depot.

Built at British Railways’s Derby Works, 12099 entered service in 1952 and was initially allocated to Nottingham before spending time at Willesden, Springs Branch in Wigan, Crewe South, Nuneaton, Rugby and Bletchley.

Withdrawn from British Railways service in 1971, 12099 was purchased by the National Coal Board and worked in South Wales and West Yorkshire before being sold for scrap in 1989 when it was purchased by the Severn Valley Railway.

The overhaul of 12099 involved removing and overhauling its English Electric six-cylinder engine, descaling the water jacket, honing the cylinder liners, and fitting new piston rings, reconditioned fuel pumps, and injectors.

The brake gear was found to be extensively worn, so new pins and bushes were fitted throughout, and two Westslack brake adjusters were fitted instead of the original turnbuckle types.

One of the railway’s volunteers is a DC electrician and he overhauled the main electrical generator, although that required more attention than originally envisaged.

This included recutting and skimming up the commutator, replacing the main bearing, and metal-spraying the housing to restore worn areas before machining it back to size.

A replacement radiator has been fitted, as well as a new voltage regulator and battery. Externally, the metalwork has received attention and several new generator access doors fitted.

To complete the overhaul, 12099 was painted in gloss black paintwork, British Rail transfers were applied, and its cab numerals received a fresh coat of paint.

Unfortunately, the overhaul of 12099 was not completed in time for the Severn Valley Railway’s recent ‘Diesel Bash’.

The railway recently celebrated the first anniversary of its partnership with Network Rail where each organisation benefit from the other’s expertise, technology, and facilities.