December 11th, 2016

Diesel Department – December 2016 Update

It’s been a while since the last report, so here’s a rundown of what’s happened to our Diesels as of late.

Class 117 DMU

We completed the bodywork repairs and repaint on the DMS car in June 16, having started the railcar project in September 2015 – however, the project has since stalled.

On closer examination, the DMBS (the car with guards van) bodywork was found to be in a far worse condition than initially thought – both internally and externally – and we have been struggling to source the parts to make up replacement bodywork ribs. The shed working space was also fully occupied, which didn’t help. Some mechanical and electrical maintenance work did take place on the two cars, with the engines started up and maintenance on the final drive etc. Thankfully, after much hunting, a supplier of body parts was found.

The team required a sheet steel bender, which is a type of bodywork forming machine and a heavy-duty tool bench, to allow the fettling and bending of the fabricated sheet steel into the weird and wonderful shapes required to reskin a railcar.

The team were told that the railway had obtained a heavy-duty bender, which may be suitable, as a part of a job lot of engineering equipment sale. On examination the basic machine, which is very old, was found to be sound but had several key parts missing. One of our engineering staff – Barry – was certain he could fabricate/remanufacture the missing components. This entailed a lot of forming, milling, drilling and turning. I have to say that I was impressed with the standard of workmanship obtained. When compared with the original parts used as patents, a perfect match was obtained. I did my bit in cutting down and shaping the end of the new, heavy-duty steel bending handle.

mike f checks the railcar profileThe complete machine was rubbed down and given a coat of silver Hammerite, before being set up and tested. In common with many of us volunteers, she may be old and silver on top but she worked perfectly when making up a test piece.

We’ve also scoured North Weald Loco site, looking for second hand wood suitable for the new heavy duty tool bench. I was surprised that in the end that the only new materials required were heavy duty coach bolts and a special type of screw to hold the main frame. As with all things, we were fortunate to have an engineer to give direction and the correct tools for fine tuning a tool bench made from scrap materials.

Back to the DMU, the DMBS is now set up in the shed, complete with access tower and working room. We hope now, with all preparations complete, to start properly on the body in January 2017.

DEMU Thumper 205205

After the diesel engine started misfiring on start up, it was decided to overhaul the injectors. However, on stripping down the cylinder heads the cam shaft support bearings were found to be discoloured, having at some stage in their life run hot, and would therefore need replacing. On removing the cam shaft, the key way (which connects the cam shaft to the drive cogs) was found to be badly worn, which may have caused the misfiring.

We are at the stage that investigations on whether to repair or replace the cam shaft are ongoing.


Class 37 D6729

The Class 37 failed in service with an earth fault shutting down the engine; luckily, the engineer who looks after the diesel maintenance was driving the loco at the time. The fault was traced to the coolant fan clutch control circuit – this was a dead earth and could not be cleared in-situ, so the train was hauled back to North Weald by the Class 31.

The fault was found to be caused by the fan clutch having become worn and subsequently slipping, causing the housing to overheat, which in turn caused a relay control unit (mounted on the housing) to melt and short out the wiring, that then caused the earth fault. We also found that the seals on the fan clutch control box had perished, and rain water was seeping in.

The fan clutch was replaced (quite a substantial job) and the control circuits were rewired. The control box was stripped, rebuilt and remounted in number one cab, in the space once occupied by the cooker.

While performing daily maintenance on the 37, it was noted a strange noise was being emitted from the main generator, later found to be defective insulators. Remedial work was performed by specialist external engineers.


Class 31 31438

Apart from the normal maintenance work, which includes cleaning traction motor and main generator commutators, this loco has been her normal reliable self. At present, she is providing Electric Train Heat and assisting with traction power for the Santa specials.

While working one of these, she failed with a very unusual fault. The feed cutoff valve (which is part of the loco safety system, feeding main air in to the braking system) did not open from number two cab. Our engineer quickly changed the valve, but the fault did not clear. A quick think and check of the mechanically controled air valve, housed in the base of the driver controller pedestal which in turn controlled the feed cut off valve, turned up the cause to be the valve was sticking. Our engineer freed it up, and the feed cutoff valve then opened and the main air system fed the braking system as normal.
Large sighs of releif were heard, and on we went with the Santa specal.  At the close of service, our engineer stripped and cleaned the valve.

Class 47 47635 “Jimmy Milne”

The class 47 is stopped pending repairs to the roof. At present, the two middle sections have been released, ready to be removed for repair – all awaiting shed space for the work to be carried out.

Class 25 25173

Making slow progress on the body work overhaul with our external engineers.

Class 03 03170

Ongoing maintenance work on the braking system, con-rods and axle boxes.

Class 03 03119

This Loco was stopped due to being unreliable. The diesel engine was shutting down without warning, the cause being the diesel engine guvnor; remedial work has been carried out.

Class 55 55019 “Royal Highland Fusilier”

37 Meets 55

When I was a young trainee train driver, we had jobs where we went over to Finsbury Park to pick up freightliners. We used to watch Deltics pass through, coming from and going into Kings Cross, their distinctive engine note like no other.

Apart from helping move them around Stratford Loco Depot to the DRS Repair Shops for engine changes, I never had any Deltic experience, so you will understand why I jumped at the chance to spend a day piloting and driving the visiting locomotive during the Autumn.

I must admit, even at my advance years, I was very excited at the prospect. I helped with preparation duties and organising the shunt movements; however, I was not prepared for the strange sounds on engine start up. The Deltic engine sounded more like a cement mixer than a highly tuned diesel engine!

My overall memory of the Loco was – aside its unbelievable amount of tractive power which required extremely careful handling – the noise; on engine tick-over, my body was vibrating with hum; at times, the noise was so great that it became painful. I have to admit gave up the chance to work on the Deltic for a second day – my hearing would not stand it. I elected to downgrade myself to driving a visiting 08 Loco instead – a much quieter ride…

Until next time.

Chris Travers
Diesel Restoration Group