Work to rewire the wheelslip protection circuits on 56006 has continued over the winter but unfortunately the work cannot now be completed soon enough to allow the full testing and proving of the work and then the essential test runs(s) before the upcoming Diesel Gala. Work will continue but the locomotive not scheduled to appear at the gala.
The wheelslip resistors form part of a quite complex circuit which in essence identifies a slipping wheelset by detecting the different electrical characteristics between a slipping traction motor and a non slipping motor.
The work has involves stripping out the old resistors and wiring- identifying each wire and matching it to the wiring diagram. Then finding a supplier for the correct grade of cable – the resistors get very very hot and the cable has to be rated to 1900v at 190 degrees C. The cable cost was in the region of £150 . The resistors were sourced at a cost of around £1000 from a specialist firm – who needed no other information other than- “can we have a full set of resistors for a BR Class 56 locomotive”.
The correct cable crimps had to be sourced – all to the correct specifications for the application, and these were a very specific railway spec only made by US company TE Connectivity. Understandably these were well researched before purchase as they were quite expensive and not easy to obtain.
The replacement cables were made up to match the existing lengths of cable and then made up into looms to keep the wiring as neat and tidy as the original cabling.
Then when it came to refitting in the close confines of the electrical compartment on 56006 , it became apparent that the job of wiring up the circuits in a main workshop- where the whole electrical cubicle was removed from the locomotive , was much easier than the job we had to complete. The biggest issue was the tools required to crimp the cables which enter the rear of the wheelslip resistor compartment were too big to fit in the small space we had to work in. After several different tools were borrowed and tried we eventually located a compact pistol type tool which could be operated with one hand. This was critical as the crimp had to be held with one hand and the crimp tool operated with the other. There just wasn;t physically enough room for a second person to get their hand into help – so it had to be a one man operation. The tool, which was ex RAF and cost £300,only arrived a week ago but was perfect for the job and the cables were crimped up in a 8 our session yesterday.
The cable looms to the resistors now need to be fitted and the whole job checked against the wiring diagram to ensure the wires have all been replaced exactly as they were. Any errors could result in damage to the locomotive – by damaging other circuits on the loco or worse of all cause a fire , so we make no excuses for not rushing this work.
The cables have all had the identification marks renewed as this will help with fault finding and be a great help if we ever have to replace any resistors in future.
We are sorry the loco will be unavailable and we have kept the ELR Gala team updated as we progressed the work. We are confident the work will result in a more reliable 56006 – and we actually found a number of broken connections when we removed the resistors so part of the circuits may not have been working for several months or years. The fitting of the overall tarpaulin has made the loco very very dry inside and this should also help eliminate many of the damp related faults we’d been seeing.
The small ( too small) team of volunteers are confident that 56006 will be returned to operational status in the next couple of months and it is our intention to have it available for the next gala in the Autumn.
– we do desperately need more volunteers to spread the load and the knowledge , as trying to coordinate work party dates when several key volunteers working shifts is just another restriction to making progress with any repairs on 56006.
Please get n touch if you feel you can help out at Bury