It's been a while since I added anything to this site. So I'm just updating on my engines. The 'Romulant', now called 'Bluebottle', ran quite well until the boiler test and the leaking tube. I'm still waiting for Wayne Bell the boiler maker to remove the tube so that the rest of the tubes can be examined. I suspect that all the tubes will need replacing. After four years running this has put me off steel boilers. So my next engine will have a copper one and hang the expense. Much discussion when water has taken the blame, and we came round to copper tubes. Everybody knows that copper tubes in a steel boiler will cause the tube plates and the firebox to rot out. So the question arose; did I have copper tubes in the boiler? And the answer is YES. It is the tube from the regulator to the wet header. It never even occured to me at the time. So, when I get the boiler back, I'll replace the copper with stainless steel. I'll also do the same with the Hunslet. Maybe that will help, anyway it can do no harm. I also put in too much additive accidentally and during the afternoon a ball valve stuck open and the boiler blew down via the injector. Hasty dropping of fire followed.
This loco must be the most photographed engine in Wales. There are dozens. It runs on the Brecon Mountain Railway. "Youtube" has some excellent footage of this engine in action. Built in Germany in 1908 at the Arn Jung factory and restored in 1972. I wanted to build this as the next project, so I got permission to go and measure it up. It was in the workshop with quite a lot of work being done on it. I was able to get all over it, measure and take plenty of photos. I was very impressed with this engine. No expense was spared at the time and even the driver and fireman have padded leather seats! The one picture I needed was a side view, but this wasn't possible so I've taken one from the internet supplied by two New Zealand walkers. So, if I have infringed on any copyright please let me know and I will remove it.
My first problem is one of scale. The track is 1ft 11.5inches which means I need to scale it to 0.3 times. Now I have a limited amount of carrying space and as the engine is around 20 feet long, this exceeds my limit. So I'm going to cheat. Originally it was used on a 60cm track and also on 80cm. Neither size works for me. The wheels are inside the frame so can be placed almost anywhere I like, so I'm going to build it a quarter size. This makes the track about 2 feet 6 inches; a common size. Since the wheels are barely visible, nobody will ever know unless it's compared beside another model. I know too, that this loco has some modifications, so perhaps I'm not too amiss. It never had a tender, for example.
First job is to do a rough drawing of the boiler to give to the boiler maker (Kingswood Boilers). He has given me a preliminary date for
the middle of 2011 but I need to pay a deposit to confirm this or I might have to wait until 2012.
So a lesson in firing steel boilers followed. Make the fire right up to the bottom of the firehole and use the largest size coal possible. Never have a white hot fire. Don't use an electric blower to start the fire as this will eventually cause tubes to leak because of the different temperatures between smokebox end and the backhead. If you have to drive with the blower open to maintain pressure, then decrease the size of the blast nozzle. This was a very expensive lesson. So at the moment I'm rebuilding the engine ready for next year.
I was never happy with the way my Hunslet ran. It always seemed to go better backwards than forwards. On mentioning this to a friend he put me in touch with Don Ashton the leading expert on Walschaerts. Don has been marvellous, and spent several weeks going through each stage as I changed things. He took my dimensions and ran them through his simulator. In the end I made eight of the rods again! Some weren't very far out but I didn't want to botch them. The simulator gives dimensions down to three decimal places so a compromise had to be made in places. Then finally I set up the valve position. Not the old way of lining the edge of the valve with the edge of the port. The simulator gave a position for the piston which was 5.364mm before forward dead centre, then the slide had to be exactly over the centre of the ports. Don says that if I've stuck to all the measurements, then the valve gear is as close to perfect as can be made. I look forward to boiler test day and trying it out.
The rest of the time has been spent on drawings for the Graf. This is much harder than having a GA drawing. Using measurements and photos and trying to get proportions right, is not easy. However, once I've finished rebuilding 'Bluebottle', then I will start to cut metal.