Weekend Rails

what we do for our kids

Of Tom and tribulations

30th September 2012

"Tom" has caused a lot of head scratching this week. The leak from the converter rear seal was concerning. Technical advice was that it might seal itself with a bit of running and warmth., but we weren't confident. It is not that we don't trust the guy who rebuilt the converter, but I have made it policy never to do a converter in an ordinary workshop. The carbon seals are pernickety - well, let's be honest, the technology is over 50 years old and there are probably better seals out there if you wanted to invest in development - certainly Nico, the Japanese licensee for Twin Disc, assured me 15 years ago that their converters don't leak.

But Twin Disc themselves have not changed the design and the seals must not be touched with bare fingers (acids present on your skin will attack the seal) and the atmosphere must be clean and dust free. I have been persuaded, by fitters then in my employ, that they could re-seal a converter on-site at much reduced cost and turn-round time. I let them try, and then had to have it out again to send to the professionals with the right workshops. Besides, it is roughly 4 years since this converter was rebuilt and its storage in the interim may have been the cause of the seal drying out and 'grabbing'.  So much of our discussion revolved around whether you could extract a converter from a Sentinel 0-6-0 such as "Tom" without taking out the engine and converter as one lump. I maintain that it is do-able, otherwise I would have known about it from the my days at Thomas Hills.

Andrew popped in to Rowsley late on afternoon during the week to see for himself, both the leak and the space available, and conceded that maybe it could be done, though it would be cramped. While there, he made a start painting the insides of the casing parts for "Libby" in white.

The outcome of these deliberations was that on our next visit to Rowsley we would try to get "Tom" running and see if the converter would seal on its own, and if not maybe attempt to dog-up the rear bearing retaining nut (already supposed to be at 350lb/ft) in the hope that that might set the seal better. Only then would we resort to taking it out, one way or the other.

Plan A had been to get up to "Pluto" at the DVLR on Saturday, but although the pump is ready and waiting, I had not had time to order the filters or sort out the necessary fittings to carry out the planned mods to the fuel and oil systems to prevent a recurrence, so we headed instead to Rowsley.

With the clutch cylinder finally reconnected to the arm, oil and water checks carried out we fired "Tom" up and allowed the air pressure to build. I was pleased to note that it unloaded dead on 100psi and having made the necessary precautions, I engaged the clutch and felt the satisfying tug and heard the change in engine note as the transmission engaged. Andrew insisted I tried to disengage and that was not so satisfying, the clutch cylinder twitched but did not succeed. Andrew pushed the clutch out with his boot and decided to ride on the running plate.

With responsibilities thus determined, I re-engaged the clutch, released the brake and "Tom" set off gracefully up the loco shed spur, propelling Drewry "72229" as insurance. Engine smoke cleared a bit as the temperature rose - this was, we understand, the first time that the loco has moved under its own power since 1993. I reached the limit of our run for test purposes and gathered that Andrew was distinctly anxious to get back, so with slick co-operation, the clutch was disengaged, the gearbox reversed and "Tom" proceeded back to the loco shed. As soon as I get to its stabling point I got the "cut it" signal from Andrew. The euphoria of achieving its first powered run was not long in evaporating, for having held water for several weeks, the first time we had had sufficient temperature in the block to create pressure and the radiator had sprung a serious leak.

That decided it. "Tom" not only had a significant fluid leak at the converter end, it now had an even worse one at the radiator end. Andrew has a refurbished radiator (acquired as a strategic spare from Jarvis) but having to disconnect so much of the power unit anyway, the whole thing might as well come out. We drained off the coolant, and moved inside to set up his MIG welder. The relay lever for the handbrake linkage on the 03 and the calliper bracket for the 03's parking brake were duly assembled. But before we called it a day, we had offered Harvey our services and rather than occupy the steam loco at the end of its day, 72229 was fired up, brought one half of the 2-car dmu out of Rowsley shed, and popped round to collect a carriage to take its place. As driver, I brought the camera but got no chance to take a picture, and with Harvey as shunter, Andrew wandered off to talk to Ben, so no pickies...

Sunday, and by lunchtime we were back at Rowsley and making a start on disconnecting all that we could without making the loco unsafe to move. So propshaft, throttle linkage, starter cables, exhaust system, casing bolts, engine mounts, radiator mounts, coolant hoses, fan belts, wiring and hoses were detached or loosened off ready. The oil was duly drained out of the converter - thank heavens we put that drain line in - batteries disconnected for safety and plans made for Andrew to have a day off and lift the power unit out. The converter can then come off on the floor and be turned round in 24-48 hours with new seals and with a bit of luck, we'll be back to running before the end of October. We also stripped the clutch cylinder, and with a set of new seals it should be recoverable.

It was of course Andrew who observed that this was the last weekend of the month, and that maybe we should have left Tom's inaugural run until next week. We'll never know.


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