City of Derby’s overhaul: an update from the workshop
Earlier this summer, we shared a first look at the work being carried out on City of Derby, one of our two large passenger diesel locomotives. Since then, the project has developed into a comprehensive overhaul, with improvements being made from the wheelsets right through to the driver’s cab.
City of Derby is an incredibly important member of the Lappa Valley fleet. During the winter, she operates many of our lilac timetable services, allowing our steam locomotives to enjoy a well-earned rest and giving our workshop team valuable time to carry out maintenance.
During the busier summer months, City of Derby can also be called upon to haul a second train or take part in ‘top-and-tail’ operation, with a locomotive positioned at each end of the carriages.
Having arrived at Lappa Valley in 2016, City of Derby underwent her first major overhaul during 2020 and 2021. That work kept her running reliably through the seasons that followed, but the quieter period for our diesel locomotives has now provided the perfect opportunity to give her some further care and attention.
Major work beneath the locomotive
City of Derby is currently resting on what are known as ‘ambulance bogies’. These are temporary wheeled supports which allow the locomotive to be moved while her proper wheelsets are away with specialist engineers.
The wheelsets are receiving extensive work, including wheel reprofiling and new axles. We are also improving the chain-tensioning system, uprating the chains and servicing the hydraulic motors.
Together, these improvements will help ensure that City of Derby is ready for the demands of hauling passenger trains for many more years to come.
Improved cooling and hydraulics
The locomotive’s hydraulic system is being thoroughly flushed and serviced, including the hydraulic tank and cooling equipment.
A new engine radiator has also been fitted in a slightly higher position, while the water flow between the engine at the front of the locomotive and the radiator at the rear has been adjusted for the best possible performance.
During the busiest parts of the summer, City of Derby can be asked to haul longer and heavier trains. These changes will help her remain cooler and make her even more dependable when working hard during peak periods.
Engine servicing and testing
At the heart of City of Derby is a 2.8-litre turbocharged Isuzu diesel engine, based on the type once found in the Isuzu Trooper but specially modified for use in the locomotive.
The engine has received a considerable amount of attention during the overhaul. Work has included replacing the rear oil seals, fitting a new timing belt and completing a full service with fresh oil and new oil and air filters.
It has since been started, tested and is running extremely well, with only a few finishing jobs still to be completed.
A complete electrical rewire
One of the largest elements of the overhaul has been a complete rewire of City of Derby.
Electrical systems naturally evolve over the life of a locomotive as equipment is added, improved or removed. This overhaul has allowed the team to tidy and simplify the system, incorporating changes we have wanted to make for some time and ensuring everything is in the best possible condition for City of Derby’s return to service.
The locomotive’s air system is also receiving a major upgrade. A brand-new air compressor has been installed, while the system itself is being standardised to work with the single fail-safe braking system now used across Lappa Valley’s passenger fleet.
City of Derby had previously been configured to operate with two different braking systems. The new arrangement will be simpler and more efficient, while also supplying auxiliary equipment such as the locomotive’s horns. Specialist colour-coded air pipes will make the system easier for our engineers to identify and maintain.
A redesigned driver’s dashboard
The driving controls are receiving plenty of attention too.
There was a considerable difference between the cab layouts of City of Derby and our newer diesel locomotive, City of Truro. We are therefore using this opportunity to create a dashboard which is more ergonomic and straightforward for our driving team.
A full-size timber mock-up has been produced, allowing us to test the position of switches, gauges and other controls before committing the final design to metal.
The finishing touches
Once the mechanical and electrical work is complete, City of Derby will be treated to a fresh coat of paint. Her nameplates have already been carefully rubbed back and will receive new paint and a polish before being returned to the locomotive.
As Ben explained in his workshop update, City of Derby is “a really key player in our fleet”. Although she may currently look as though she is in a million pieces, her return to traffic is hopefully not too far away.
We look forward to sharing another update and welcoming City of Derby back onto the Main Railway once all the work has been completed.
