Took it to the track and with a good few others, I started up the fire and waited in the queue. It soon came up to 80 psi and I was about to call the inspector over when I was suddenly enveloped in steam! On opening the firedoor I could see water pouring down on to the fire. Has to be the fusible plug. Took it home and with a block and tackle hoisted on its front end letting me get to the plug. I don't use a fusible plug because with the smaller steel boilers they can melt out for no apparent reason. I had not intended to take this plug out - ever.

I'd made the plug with bronze as recommended and with a good big hex head for a socket. A proper six-sided socket, not one of the multiple things. I couldn't shift it and in the end it rounded off. Nothing for it but to drill it out and retap. Three days it took me but I finally managed it. The main problem being the little bits of bronze didn't want to come out of the threads. So I made a new stainless steel plug with a 16mm socket head and fitted. New test arranged. I pressure tested it to 200 again. Nice fire going this time the cloud of steam appeared at 30 psi. There had to be a hole. I couldn't see one.

Long chat with the boiler maker who talked of worm holes which I gather can sometimes, though rarely, occur when welding in stays. I gather that it is a pocket of gas which eventually makes its way to the surface creating a hole. So bring it along he says and I'll have a look. Just like that. It took me the best part of a day to strip the engine and hoist the boiler on to the trailer. To cut a long story a bit shorter, he couldn't find a hole and no evidence of a leak. So, he put in another line of weld all round the seams and the stays including the fusible plug. All I can do is hope that covered it.

While I was there I asked if he could shift the steel washout plugs as I couldn't. So he welded a bar to each and bent the bar; more drilling out of plugs! We had a long chat about plugs. Never use stainless steel as its expansion rate is very different from boiler plate and will gradually leak; so much for my new plug. Only use cast iron or bronze. How to get them out? I'd used the recommended foliac manganese, messy and no good. Latest thinking now is copperease grease and PTFE tape - comes out every time!! I certainly won't be using bronze again.

One tip he had been given by the more experienced was that if you get a weep round the tubes which are expanded in place then to seal them, take a small quantity of rice water next time you are cooking rice and pour in the boiler next time you run it and that will do the job. I wonder how that was discovered?

So with the Romulant in pieces and the Hunslet untested, I've no engine to run. So I did a pressure test on the engine; no problem. Got it on the stand in the garden, blocked up the suspension to stop the axles dropping and jacked up the rear end so that the driving wheels just cleared. Before jacking up, I got a fire going and watched the pressure come up. I'd forgotten to set the safety valves on my tester so even when screwed to their lowest I could only get 40 psi. So I jacked it up and opened the regulator. A somewhat reluctant jerk or two and away it went. I left it gently ticking over with the safety blowing off the whole time. I had intended to let it run for a while but it didn't look too safe so I shut down the fire and let the engine run until it stopped. It did so at 18 psi: very pleasing. I didn't want to drop the fire while it was still hot on to the lifting trolley so I waited for it to die. Within a few minutes the almost dead fire had the safety blowing off so I seem to have the boiler design OK. All the while there was hardly any difference in water level. I was always unsure how I'd get on when removing the grate through the firedoor but it hooked out with a bent rod no problem as it was in two pieces.

Those were the good things; now for the bad. One side tank and the bunker tank have small leaks even though I had tested them and for some reason the axle pumps don't. So I have to strip the engine to get the tanks off which means I now have two engines in pieces and no engine to drive. Good job I'm retired.

13 April 2009

I soon found out why the water level seemed constant, it was linked to the axle pumps. They were working; it was just that the tap was stuck and the handle was moving without changing the position, so water was being pumped into the boiler all the time. Soon cured. Quite a different story to cure the leaks in the tanks as they had to come off.

I arranged for a boiler test at home and also a witness. No major problems, just little ones like the sight glass decided to leak at 200 psi but was perfectly OK at 100 for the safety valve check. Also a few wisps of steam where the gland packing wasn't quite right, but it passed and I put those things right. On the Friday work day, I took it up to the track for its first run. Sounded very nice but I have decreased the size of the blast nozzle as I felt it was a bit on the breathy side. Major problem was I had to run it notched back two notches. When I'd had to move the reverser I'd altered the reach rod by measurement and now it was too long. I hope I've got it right now as I'll be taking it to a running day very soon. I should really have taken off the top of the steam chest to get the timing right but it's a major job taking off cleading etc. If it's not right after the running day then I'll have to do that.

************

So here it is on the steaming bay just as I'm about to light up. It was bank holiday Monday, cold, wet and windy! I should have gone the day before. It was stiff to push along but a couple of laps cured that. I thought I'd need to tighten up the suspension but I found the soft ride took up all the shocks. I ran most of the afternoon with two carriages carrying passengers. It proved to be very powerful and took the gradient much more easily than the Romulant and maybe this was due to the smaller wheels. It gave a better ride too, probably because the centre of gravity is lower. The photo also shows my new driving truck. Actually, it's just a new top with the same chassis. I have also made a large brass, water tank centrally which helps stability. The other top, apart from being the wrong colour, was too wide and gave me cramp in my hips - old age catches you out at times! I did have one worrying moment when one of the safety valves didn't start up and the pressure went up to 120psi before I got the pliers and gave the shaft a pull. It soon went back down.

It took a while to get used to firing with the long, thin grate but the fire burnt evenly, although I'm not sure what effect the two dampers had. When I got home and cleaned out the smokebox, it was obvious that the blast nozzle was too small and its ferocity had sucked off the top of the fire and two of the bottom tubes were blocked solid. I've replaced it with the original 10mm diameter nozzle and wait to see the result, next time I run. Not sure whether all that work making the copper top was worth it! Within a few minutes of being hot and sprayed with water at start up, it just looked dirty with hardly any copper showing.

I had carefully changed the length of the reverser reach rod by the distance of one notch but it still seemed to go backwards better than forwards, so, nothing for it, but to have the steamchest cover off and do the job properly. I had used a spark arrestor of the type that pushes into the top of the chimney as a temporary measure. It worked, but much of the escaping hot stuff got by underneath and landed on the engine with unfortunate results. Some of the pieces were so hot that they burned into the acrylic paint. Shame. This never happened with cellulose.

So, not a lot to do to put things right. In the mean time I have been working on the Romulant. I've had most of it to pieces and checked all bearings etc. and I'm now re-assembling. I shall have to sell it as I'm running out of space now that I'm thinking of my next loco. The paint work is still looking good so I won't need to repaint anything. Maybe just a few screw heads which have had the paint polished off!! I have decided to try to sell copies of the drawings of the Hunslet which will be in book form A4 size. Bit of work to do on them yet, after all, there are 68 of them.

6 May 2009

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