After over three years tucked up in the comfort of No3 road at Barrow Hill, Sherwood Forester did not want to leave for its seaside holiday and so it put up a determined fight over the four weeks leading up to the Swanage Diesel Gala. There’s nothing like a deadline to focus minds and raise stress levels, but our team of volunteers and the co-operation of Barrow Hill made it all happen.
While work was being finished off on the cabs, bogies and nose ends, electrical tests began on the control circuits to re-commission the overhauled compressor. Unfortunately this was held up due to the battery isolating switch shorting out with much arcing and molten copper splattered on the engine room floor, so this had to be rebuilt. Next problem was the engine started OK but the auxiliary generator refused to supply any output volts, and a change of voltage regulator (AVR) made no difference. With no volts from the auxiliary generator, the electrics were running off the batteries, which were not getting re-charged by the auxiliary generator, so not a good situation to be in. The armature continuity resistance seemed to be all over the place instead of being very low, and we were fearing the generator had lost its magnetism or worse. Fortunately, Chris and Paul from Bowers were on hand and tried the simple thing first – they cleaned up the commutator surface with some emery sticks. Imagine the relief when the engine was started and the auxiliary voltmeter rose to 220V!
After that little scare, the overhauled blower motors were whirring round nicely, but the compressor was still playing dead. Remembering the previous lesson, the armature was wiped clean and brushes given a few flicks, and this did the trick. Finally the vacuum exhauster was switched on, and all the auxiliary machines were back in business. Something to smile about, but not for long…
A few days later, a new electrical fault appeared while testing the power circuits, with the loco refusing to take traction from the end facing the turntable, as if it was trying to stop us driving it out. This proved to be extremely difficult to trace, as we found the cab wiring had been modified from the official wiring diagram. A broken wire in an underfloor conduit was eventually replaced, and amps were once again restored to the power handle.
Having completed the repaint of the bogies and reassembly of the sandboxes, Adam and Jacob moved on to an underframe examination from the pit, checking traction motor and gearcase oil levels, greasing bearings and brakegear. Four brake blocks were considered to be worn and renewed, but one of the brake cylinders was found to have a seized slack adjuster, preventing the block from being changed. This turned into a mini recreation of one of the less appealing jobs from the days of yore at BR depots, as the brake cylinders are bolted inside the bogie frames and weigh about 100kg. Gravity is in your favour when removing a brake cylinder, as long as fingers are out of the way. Bolting a brake cylinder back up requires shoulders made of RSJ and much grunting. Typically, when the old brake cylinder was dragged out, the slack adjuster decided to unseize itself, but it was replaced anyway after all the effort, just to be sure.
Finally the loco was ready to leave the comfort of No 3 road in the roundhouse, and the somewhat nerve wrangling procedure of jacking up the pony wheels was carried out, so that the loco could fit on the turntable. Steel blocks have to be used to transfer the weight on to the remaining wheels, putting extra stress on the leaf springs. The loco was driven as a Co-Co on to the turntable, and everyone was thinking it would be parked up on the exit road in 10 minutes and then time to wash up and head home. But no – the turntable turned about two feet and moved no further, with the drive wheel spinning unable to get any grip. Sand, rubber pads, pinch bars and other forms of persuasion all failed to move the turntable after two hours of frustration. Eventually a block and tackle was slung between Sherwood’s drawhook and another loco, and the turntable started to creep round till it lined up with the exit road. Yet another late finish.
Earlier this year the loco roofs were sent away to be repaired at local engineering firm Victoria Fabrications. The main roof had the large silencer well completely renewed, and the boiler room roof had to be patched. After sand-blasting and spray painting, the roofs were craned back on only to find the bolts holes no longer lined up due to distortion of the framework. One corner of the main roof was sticking up 6in, and could only be pulled down on the inside with a ratchet attached to the engine bedplate. Another day was spent connecting back the silencer to the turbocharger and bolting down the boiler room roof.
The batteries on Sherwood dated back to 1995 and were on their last legs, so two new sets were supplied by Shield’s and swapped over by Shaun, each cell being disconnected and replaced with a new one, 96 times over! The difference in starting was immediate – the engine instantly fires up and almost takes off.
Moving anything by rail is proving to be more and more difficult due to the paperwork that has to be created to satisfy different parts of the railway bureaucracy. It used to be only axle test certificates that have to be redone every two or three years, in keeping with the frequency of testing in BR days, when of course the loco would have done many thousands of miles. Once again we welcomed Graham who has been testing Sherwood’s axles in preservation for the last 25 years, and still found no hint of a crack on his ultrasonic test gear. Its amazing that he used to drag around a large oscilloscope on a trolley, but now has a hand held box of tricks – next time it will probably be an iphone app. For our trip to Swanage, someone in a far away office decided that Sherwood’s axle bearings were obviously ready to collapse the moment we rolled on to the mainline. These people live in a surreal world of risk assessments, so we were obliged to “mitigate the risk”: a detailed bearing examination procedure was written and then carried out, and then duly recorded on a form. Back in the real world of engineering, all the bearings were pumped through with new grease, a task that took many hours with an air pump. Everyone happy!
The other new paperwork challenge was due to someone in another office deciding that Sherwood must be too big for Network Rail’s tracks, as it seems that any former BR rolling stock is deemed to be too big, unless copious amounts of calculations are done at vast expense. In their surreal world, tunnels and bridges have got smaller since they were built a hundred odd years ago, so trains must also be made smaller. Well an old BR diagram with the relevant dimensions was found, and the problem went away as if the loco had shrunk by magic.
Knowing that everything was being thrown at getting Sherwood and 37057 ready for Swanage, the Fitness to Run Inspector delayed his visit to Bank Holiday Monday, the day before departure. As well as a detailed check of the loco’s wheel profiles, air brake tests were done, and the paperwork for axle tests, pressure vessels and bearing examinations were duly presented. Even at this last minute, Sherwood staged a protest with slow brake cylinder pressures and even slower air pump up time from the 37. Numerous adjustments late into the evening eventually sorted out the problems, and as it turned out, the Class 66 loco hauling the convoy the next morning had no trouble in pumping up the air systems. And if you thought we had it bad, the team on 37057 did not finish till 1-30am after changing a rad fan drive that failed at the last moment!
So after a 3 year overhaul of its engine and restoration work described in these reports, Sherwood headed off on its holiday tour of the south. Most of the work has been done by volunteers, many of whom are new to loco restoration and never saw the Peaks running on BR, so they should all be congratulated on their dedication and determination.