The Lappa Valley Railway has issued an update on its overhaul of City of Derby, one of its large passenger diesel locomotives.

The loco, which arrived at Lappa Valley in 2016, had some work done on it in 2018, and was then withdrawn from service for an overhaul the following year. The locomotive’s last overhaul was carried out in 2020-21.

It is now to have a further overhaul, and the railway expects to be carrying out work to improve its wheelsets, driver’s cab and more.

The railway describes City of Derby as “an incredibly important member of the Lappa Valley fleet”.

The loco hauls many of the lilac timetable services during the winter, which allows the steam locomotives to rest and the workshop team time to carry out maintenance.

During the summer, City of Derby is used to haul a second train or to operate as one of two locomotives in ‘top-and-tail’ operation.

City of Derby is resting on temporary wheeled supports called ‘ambulance bogies’ while its wheelsets are with specialist engineers away from the site.

The engineers are carrying out extensive work, including reprofiling wheels and fitting new axles.

The Railway is also carrying out work on the chain-tensioning system, uprating the chains and servicing the hydraulic motors. It is flushing and servicing City of Derby’s hydraulic system.

The loco has had a new engine radiator fitted in a slightly higher position, and has had the water flow between its engine at the front and the radiator at the rear adjusted to maximise performance.

Work on the loco’s 2.8-litre turbocharged Isuzu diesel engine has included fitting a new timing belt and replacing the rear oil seals, alongside carrying out a full service with fresh oil and new oil and air filters. The engine has been started and tested, and is running well.

The team working on the overhaul is rewiring the loco, simplifying its electrical system.

The Railway is upgrading City of Derby’s air system, installing a brand-new air compressor and standardising the system to work with the single fail-safe braking system now used on all passenger trains in Lappa Valley’s fleet.

The team is also creating a more ergonomic and straightforward dashboard in the driving cab

It has created a full-size timber mock-up, which allows the Railway to test the position of switches, gauges and other controls before it finalises the design.

When the mechanical and electrical work is complete, City of Derby will be painted. Her nameplates, which have been rubbed back, will be painted and polished before being reattached.