THE BOILER TEST

The best laid plans of mice and men.......etc.

Having collected a new trailer, it took much longer than I anticipated to fit rails, docking station/winch holder and come up with a quick release system for the hold-down ties and make them.
It is pointless turning up to a boiler test with a new engine without doing a pressure test at home. So it was rather late in the week to do this, when I started.
Having filled it up with water (3 and bit watering cans full!), various leaks appeared. All three taps on the site glass, all three clacks, the regulator gland and a few nut-tightening bits. All these without any pressure! Drain the system and start again.I spent a fair time lapping in the siteglass taps, re-doing the clack seats and tightening the gland bolts. Re-fill with water and start again. This went on for several times. Eventually they more or less stopped. By leaks, I mean drops appearing and not spurting out.
Time now to apply some pressure. I slowly brought it up to 50 psi and then watched the needle fall back as the leaks took over! Still one of the clacks leaking back through the injector, a small weep behind the site glass where the fitting screws into the boiler; simple to cure? Just try tightening the locking nut. I did, and there was a small click and the water spurted out. Hasty drain down. I'd sheared the bottom screw-in joint off. This part was made of bronze and it is not made to put excessive load on. So I had to dismantle the site glass and repair the threaded part. This time I made it from stainless steel. I had the problems of removing the broken pieces from the boiler and the siteglass. Still, I did it and fitted it together. The red paintwork was ruined so I had to clean and respray.
It is now late Friday and I have just one day before the test to work on it.
Saturday and I fill up with water again and bring up to pressure. The site glass holds but there is still a weep from the taps! Regulator gland OK. Suddenly a jet of water comes out of the boiler dome where the regulator bracket is bolted to it. I was always unhappy about this as it is a flat bracket bolting to the inside curve of the dome and the bolt hole would always be a source of leaks. - Drain down and remove top of steam dome. Now I'll need a new gasket and also have to make a special spanner to get to the bolt head inside which is turning when I try to tighten. Refit and fill with water and bring pressure up to 50 psi. One of the clacks starts to leak again but the steam dome is holding. Bring the pressure up to 100 psi and the weeps begin to get worse of course and then I hear an ominous sound from the smoke box. It's full of water. A small leak behind the wet header. This I can't understand as the unit tightens onto an 'O' ring. This is bad news, as it means taking quite a lot to bits to get at the unit. It didn't want to come to pieces and took me over an hour to remove it only to find the 'O' ring is OK and the leak is behind the bush which is pushed into the tube plate. This is even harder to remove and takes two hours but I did find the source of the leak. At some time during the making of the boiler somebody had cleaned up with an angle grinder and this had just touched the regulator tube bush leaving a scored mark. Nothing bad but enough to leak under pressure. To overcome this, I've used a gasket and not relied on a sealing compound.
It is now six o'clock on Saturday and I'm nowhere near ready for the test. Feeling knackered and somewhat downhearted, I call time. After all this time, you'd think I could manage to make a simple clack valve! Well I did say I'd write with warts and all! A friend of mine, now on his 13th loco, has started to use clacks with 'O' ring seats which are in line so the 'O' ring is not affected by heat.

And so to stage 2......

When I reassembled and filled with water, I had left the steam tubes unconnected and now water was coming out of the steam tube. This means the regulator is leaking and that's not possible with a new ball valve. So it has to be either the steam tube screw joint into the regulator bottom bush, or the joint into the regulator itself. Both would have to be checked. So once more the steam dome cover comes off. No point in tightening the tube as that doesn't guarantee a leak proof joint. Getting the tube unscrewed when it's thin copper and only an inch showing is not easy. But I've done it before. I turned up a tapered piece of nylon and pushed the plug in hard without belling out the end. This I could grip and turn.

Next morning I decided that as I was going to have to get the regulator out to check the other screw joint, that I might as well make another bracket with a curved back plate, something I should have done in the first place. This time I made it from 3 mm copper sheet instead of steel and then rust won't be a problem. I finally managed to get the lot assembled and filled up with water. The smoke box is DRY! Only I can't apply pressure as I've managed to break the site glass and water is pouring out. Drain down and replace. That's the end of another day.

I repaired the site glass and filled with water and let it stand. Gave it a while and took another look and found the smokebox full of water, yet again. I was sure my two joints were perfect so it had to be a leaking ball valve. A valve which doesn't leak! I could see in the top of the valve and watch the ball, so I put in a drop of water which filled it to the brim and watched. Sure enough, the water slowly receded. So it was leaking. I removed the regulator stop and moved the lever just a little. And that was all it was. All that work and the cure was to move the regulator stop just a fraction; enough to remove what must have been a hair line crack.
I managed to stop the clacks leaking and one of the globe valves. The whistle valve needed a longer spring and hopefully that will do the trick. At the moment, the boiler is full to the brim and there are no drips. I'll leave it overnight before applying pressure tomorrow.

Next morning a full pressure test and all problems seem to be solved. Just a question of waiting a fortnight for the next chance to have a boiler test.

I haven't been wasting my time waiting for the boiler test; I've made a start on a lamp. Test day came and now I had an opportunity to try out my new trailer and the holding-down ties. Winching the engine on to the trailer showed a decided reluctance for the wheels to turn. Probably rusting up in the cylinders. The engine hadn't been turned over for over a year when it last ran on air. Got to the track and unloaded. The wheels didn't turn! Had to slide it on the rails to the steaming bay.
The boiler test for steel boilers is different from copper ones, as the hydraulic pressure has to be brought up to 2.5 times the working pressure. This is done twice and each time released and then a third time and held there for five minutes. No problem at all; just an occasional pump to hold it on the mark. Next test the pressure gauge. Bit disappointing that it wasn't spot on. About a couple of pounds low. Still it passed.
Next, drain some water off and light the fire. Took a while to warm up all that steel before anything showed on the pressure gauge, but as soon as the blower could be turned on the pressure rose steadily.
The next part of the test is to prove the safety valves are working properly. The blower has to be on full and the fire a good one. The pressure gauge mustn't go beyond 10% of the full pressure - I just made it at 108psi. The fire was white hot. The blower was too fierce really, so I'll reduce the number of holes.
And so I got my certificate.

All I had to do now was drive it; but would the wheels turn? I had to get the lubricators working, so I opened them up and let the oil in. Funny how you can make two identical things and one works and the other doesn't. They were going well when one suddenly blew out the 'O' ring and filled the cab with steam oil! So no long run that day. But I did try it out on a short part of the track. I did get the wheels turning but I wasn't happy. I drove it up and down the short bit of track but something is very stiff so I'll need to get it on the stand and do some more work on it. So many little jobs. I had one scare when the smokebox became full of water but it was just that the water had expanded so much that the blower was blowing water in with the steam; not a problem. I'd been testing the injector and I'd forgotten it was on and put in too much water. At least that worked.
When I came to drop the fire with my simple system, it didn't. The heat had distorted the ashpan and I had to force it open! - just another little job.
I have made one clanger; when I'm sitting on the seat, I can't see the pressure gauge as it's too high up!

I've included a couple of photos taken at the end of the day as I'm draining down. So I've a fortnight before the next running day to get things right and I might have a steam up at home if I can get the thing blocked up and down the steps into the garden.


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I got the date of the running day wrong; it was only a week away and it poured with rain. So instead, I took the engine up to the track on a working day. I'd put right all the faults I could find, including moving the gauges lower, but I found they are still not low enough!
The biggest job was the fact that the wheels wouldn't turn. I disconnected the driving rod at the cross head on both sides. The wheels went round without any problem. I took the end caps off the cylinders and made sure they were not stuck and were well lubricated; this was not the problem. On reconnecting one side at a time, it was obvious. The top of the driving rod was coming up against the bottom of the slide bar and wedging. A little bit of machining to increase the clearance and everything was OK. I checked back with my CAD work and found that I had assumed that the two rods were closest at top dead centre which proved to be wrong; more like five degrees past. This, coupled with the weight of the boiler depressing the springs more than I expected, narrowed the gap. Unfortunately, there is no easy way to increase the tension of the leaf springs.
I was too busy to get anyone to take photos but somebody did and I'll try and get copies. At least the ashpan worked properly and the oilers appeared too but I'll need to check them. Both injectors worked well. The pumps put on quite a load when feeding the boiler, so I'll probably only use them in an emergency.
Design wise, the pony truck does require care when loading and unloading as any lifting and it drops out from between the self guiding springs. It would have been better if it had been tied down with a second point and not rely on just the pivot point. After all that, I am ready for the next running day in about a fortnight's time. That gives me plenty of time to iron out the minor things and start work on the lamp and the nameplate.

FIRST RUNNING DAY

Took it for the first running day and began with a few solo circuits of the track just to make sure of things and get the feel of it. Just one or two things need some attention but nothing major. One thing I did forget, and that was the spark arrestor. I had one or two hot bits, one of which burnt a hole in the seat. I've included a few photos just to prove that I did go pulling passengers. No real test on pulling power as we were limited to one carriage each because of the number of locos and passengers. This fourth picture shows a friend, who is the "font of all knowledge" and whom I consult whenever I have a problem, taking it for a lap.




This last picture, shows the engine off at its best. I look quite happy too!

So what next? I will be getting out the DeWinton "coffee pot" which has been in wraps for the last two years, and get it back to running order with a boiler test and probably sell it on so I can have a bit more space.

I have been thinking about the next engine for some time and even began drawings. I have always wanted a go at the Darjeeling Class B loco; an 0-4-0 but unfortunately it scales down to something like 6 feet 4 inches; too big for me to transport. However, they did build two identical engines for the Kalko-Simla (?) line which had a 2 feet 6 inch track and this scales down to about 5 feet. Regrettably, I've turned it down. Being an 0-4-0, it will tend to buck and the overhang on this 21 foot loco is 7 feet 9 inches which scales to 23 inches. This is very long and the closeness of the buffer beams to the track might well cause problems if bucking does occur. And so I'm back to looking for my next engine once more.

Needless to say, I will keep updating this website with whatever I'm doing, until I run out of space.



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