Further Winifred work
Winifred had a fairly successful season in 2012, despite joining the fleet in the latter half of the year. 40 miles were racked up in passenger service, though not without problems. Chief amongst these was the drive chain kept falling off despite being well tensioned to prevent this. Adhesion also seemed to be a bit lacking, which I suspected to be due to poor wheel profile.
Steve and I took Winifred and Alison to Grimsby Model Engineers on a visit (for those that aren’t aware, this is the home club and railway of the P2, standard 2 tank and Holmside that visit every year. The loco performed well here but I had already decided that it would be the last run before dismantling for wheel turning as well as figuring out why the chain kept falling off. On our return the loco was stripped of motion and drive chain and removed from its wheels and placed on a flat truck. It has therefore been an unproductive winter for Winifred, with Livvy and the Hymek carrying out Pway train duties between them.
The wheel profiles were found to be hopeless. It was also a known problem that the axleboxes were getting worn. I had not appreciated how worn though and when I found out the extent of the issue I decided to do the whole lot in one job. This job was compounded by the fact the boxes are not split, being steel with a large bronze bush pressed into them. This required all the wheels pressing off the axles to get to the axleboxes, compounded by the fact the wheels are grubscrewed twice, each screw requiring drilling out. The bronze bush was then pressed out, and a new one machined and fitted. I have so far managed to rebush and reassemble the leading wheels; the centre wheelset is by its nature a longer job. The drive sprocket fouled the press and this meant the axle had to be cut to release the boxes, requiring a new axle. This was machined out of silver steel.
It was doing the work on the centre axle that revealed severe wear on the drive sprocket, the teeth being very worn. This was no doubt contributing to the chain slipping off periodically and I have, in the course of replacing the axle, provided a new sprocket. Luckily my parts box had one spare that was absolutely perfect for the task. When I reassembled the leading wheelset it was spun in the lathe to ensure concentricity of the wheels and I discovered that one wheel is out of true, which would explain the nodding donkey effect at speed. Turning the wheels will cure this.
This is the extent of the work thus far, the centre axle requires reassembly pending the machining of the other axlebox bush and this will require the manufacture of a bespoke quartering jig, as the one in the workshop won’t accept Winifred’s wheels. Once this is done I can finish replacing the bushes on the trailing wheels, the wheels can be reprofiled and the loco reassembled. This is the last big push and will result in the whole loco being in nearly new condition for the first time in a long while. I look forward to seeing how she performs without the nose bobbing, knocking, slipping behaviour of last season! It will also mark the end of an extremely protracted overhaul!