Weekend Rails

what we do for our kids

Of pipes and fans

25th November 2018

Back to normal. My thanks to all those who e-mailed to let me know that Weekend Rails was 'down', and my apologies to all whose habitual Monday-morning read was disrupted.

I am still not entirely sure what happened: it certainly wasn't a hack, most likely a problem in the server which was in any event being prepared for an upgrade. It got sorted on Monday and last Sunday's edition appeared Monday evening.

So while Bill was running around on Monday sorting it out, I was back up at Tunstead on our weekly date with RS8. The sad thing was, we had another new face - George - a fitter/fabricator no less - but the portable welder this time was again out on site, so we had to make best use of his fitting skills whereas the progress would have been more valuable on the outstanding fabrication tasks. For myself I was as usual up with a load of bits ready to fit. starting with drive belts for the compressor. I had also - at last - sorted out the fitting to go from the 5/8 inch UNF port on the engine coolant connection to get me into 1/2 inch NPT for the electric sensor, but after all that trouble, I didn't use it. For when I had collected it from the supplier, they casually mentioned that the other thread on the original fitting was 5/8 inch UNF. Now as it happens, I have temperature senders which are also 5/8 UNF but it hadn't occurred to me that that was the case. Worse still, when I fitted the 1/2NPT sender to the new adaptor the probe would not even poke below the bottom of the adaptor.. It might work; on the other hand, it might end up with an air pocket and impair the accuracy of the sender. To rub salt in the wound, I checked one of the locos at Darley and realised that I had fitted the 5/8 sender on that Rolls engine and not remembered. So the original adaptor went back in and another sender will be fitted next visit.

Without the fabricator welding away, I was able to access the cab so made a start towards the control air plumbing.

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The original air distribution point in the cab bulkhead is a peculiar brass contraption which fortunately defied the attentions of scrapmetal thieves. The pneumatic scheme for RS8 as drawn up by ICI showed the air delivery pipework to be 1.125 inch OD pipe (that's 1inch bore with a sixteenth wall) thoughout, but I had taken up a 1.25" BSP crane coupling as I suspected that this contraption was larger on the engine bay side. To my chargin, the outer thread is even bigger than 1.25 BSP, but the inner thread doesn't appear to be 1inch BSP either. Confident that sooner or later I'll find a fitting that will enable the air system to connect to it, I started in the cab, putting isolating valves in so that the various parts of the control air system can be isolated if required for testing or fault repair.

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And since the horn and horn valve were already in place, the first part to be connected was to them, with a feed pipe going up the right hand cab column, and feeding the horn over on the left - the P clips were largely intact.

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I make no apologies to purists who think this should all be executed in copper pipe. For one thing, no-one can tell the difference once its had a coat of paint, but it's cheaper to install, less likely to be stolen and the fittings I use are re-usable, so no wasted olives if I make a change. Oh and they're not 'push-in' fittings - I refuse to use them having never had one that doesn't start to leak after a while on a loco. Actually, the installation progressed after the first photo was taken - one un-isolatable pipe was laid in to form a gauge line, and another forms the first stage of the gear and clutch control system. In the course of this I realised that I was running low on fittings (or rather, that this was going to use rather a lot) but that if we had a fabricator and tackle next (this) week it would have to wait for him to finish the windows. etc anyway.

Outside Pete C and George were working on the clutch detection switch. It was a slow start - at the end of last week a piece of spare steel had been drilled ready and only the fact that the appointed tapped holes in the converter were blocked by paint prevented it being fitted. I had brought up a suitable tap to clean the holes but the piece of steel had completely vanished so they had to start again. Originally RS8 had its switch mounted on the frame and operated through the clutch arm with a lever and a tension spring to the limit switch. I didn't want the switch frame-mounted: it is more susceptible to power unit movement on its a/v mounts, plus oils, dirt and fitter's boots, so I'd left Pete with the challenge to make up a new arrangement mounted off the converter itself.

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Here's the outcome. With that put together he and George moved on to the propshaft, and the converter is now joined to the gearbox once again. This had waitted until the springs had been set up better to get them somewhere near in alignment . Now, do you remember the picture from last week? Remember how the rad fan is standing proud, awaiting the radiator and its cowl? Pete C confided that a manager had come to him worried that we might be about to run the engine with that exposed, unprotected fan up front. It made me wonder, just how do propellor driven aircraft get away with not having them safely protected? Doesn't the H&SaW act apply to them? (As I write this, I know someone is going to quote me chapter and verse...)

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Andy H meanwhile had continued painting. The casing top is now in white undercoat, as are the fuel tanks (but having been painted black first I suspect they will require further attention before Golden yellow is applied). His newly-painted control lever went into its place but as yet the linkage and bearing haven't been produced, though materials are to hand. And lastly I fitted the remaining instruments for temperatures and pressures, after a bit more judicious filing of the Tufnol insulation layer.

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I just wish now I'd incorporated the keyswitch into it, but then the electrical system hadn't been drawn up then. Yes, I know that that shows a distinct lack of forward planning, but I can't be expected to cover everything, can I?

Back at the Geoffrey Briddon Building, what have we been up to? We've had a few visitors this weekend who are very welcome but do reduce our 'productive time' (that's the official description of the few minutes in between tea breaks). On Saturday the Cummins for Adolf was lifted off the skid frame and put safely onto timbers. We had hoped to extract the remains of the old trunnion mounting so as to fit my one in its place but that has proven slightly more difficult than we expected, considering this is the same part as I fitted to Libby. I don't recall having a fight with that one - maybe it was a different Cummins design.

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We had to shuffle things around with the forklift, but in the end put Adolf's fuel tank back on properly (it has to come off again later) so that the cab bottom could be put into position and lined up to within a millimetre or so. The idea, although it wasn't carried out until Sunday, was to place one of the new cab mount brackets complete with a/v mount, into each corner in turn and back-mark on the running plate. As the latter is only 15-20mm thick, Andrew has decided to drill holes right through the running plate as well as weld the mounting pads to the running plate top. (The pads serve to keep the rubber above the running plate and thus away from any oils or other contaminants that might shorten the life of the rubber mounts.) His other main task for the weekend was the manufacture of a 'thing' using bits of channel left over from the original building steelwork, two suitable headed pins and two 2" formed pipe clamps.

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Here it is in progress. What's it for? Could that be this week's competition? Now there's a thought. Perhaps I should run one of those 'entry costs £5 plus your normal text charge'. Now let me see, what to offer as a prize... three nights at the 5-star Darley Dale Portakabin perhaps (stars to be seen through a hole in the roof, which doubles as the en-suite eco-friendly shower facility - subject to rain ), or a week glamping in the PCV? OK, never mind, I'll tell you next week. See you then.

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