No 8 (or 28)

By Journeyman

Some six months have elapsed since I penned Styx No.7 (or 27), since when my model engineering activity has been intermittent. You may remember that Gypsyhill was awaiting her first steam test which was duly carried out in the Autumn with disappointing results.

Firstly the regulator wouldn’t shut down. Had she not been on a rolling road we’d have had a runaway train! Also the blower wouldn’t shut down, the bunker tank leaked, and the whistle valve wouldn’t close, all par for the course some would say, but disappointing and needing a lot of work to sort things out. Sorting out the bunker tank meant dismantling the bunker plate work, the cab, and the balance pipes to the side tanks, and then making and installing a rubber gasket under the lid from where the water was escaping, and then re-assembling it all.    

Next was the regulator. Here the superheater had to be removed to enable me to remove the main steam pipe and then the regulator body.

I had originally honed the mating faces as prescribed by Martin Evans, ‘a quick rub on a fine grit’ (!) but this was far from adequate and had left the valve face slightly convex,  and so I spent a lot of time with ever finer grits, checking the seal with a motor brake-system bleeder vacuum pump as I went along until a good lasting seal was obtained.

Re-assembly needed a lot of care as the main steam pipe has to have both its screwed ends properly sealed into the regulator body and the smokebox super heater bush, to prevent leakage directly into the system from within the boiler.

Now was the time for an air test. With the loco on my rolling road, air was slowly admitted to the boiler and, with the regulator carefully opened the loco came to life. But would it shut down ? It did indeed, and with ever increasing pressure the shutdown was more positive as the regulator bedded down onto the body, so that was one leak dealt with. Phew!

Then came the blower. I took the whole assembly apart as it seemed as if air was getting into the pipe that runs through the boiler, and re-assembled it with new sealant, but to no avail. After much head scratching, and looking at the original drawings, I decided that the length of the thread on the spindle was too short, so running it further down  allowed the cone point to shut down onto the seating properly. Another air test proved the valve to be working properly. Phew again !

The whistle valve was found to have too weak a spring to return the valve onto its seating, so that was quickly sorted out by winding one of suitable length and strength, so now, no running round the track with the whistle permanently sounding off.

My lesson from all these capers – do air tests on everything as you go along, just as I did hydraulic tests on all the boiler fittings before installing them.

By this time winter had set in, so I’m awaiting some warm dry weather to do a home test before submitting her to Our Club Inspector. I always try and make sure I present an engine for testing that I’m pretty sure will pass, to avoid wasting the inspector’s time which is freely given.

So what next ? During my school days I had built a steam tug named Wild Cat, about 40” long, which I had fitted with a power plant consisting of a Stuart 10v engine, a homemade boiler and paraffin blowlamp. Somehow, while being stored on a shelf in my drawing office in Dorset, a roof  leak had filled it with about 2” of water, and by the time I discovered this a lot of damage had been done. So before our move to Wiltshire I removed the power plant and repaired a crack in the hull. I also started to build a new boiler as the original was a boiler inspector’s nightmare.

So, with Gypsy awaiting some decent spring weather I have returned to Wild Cat. The Stuart has been dismantled, refurbished and brought back into running order, the hull has received new coats of paint both inside and outside, the propeller shaft has been cleaned and re-greased with some of the original shaft grease - dark thick stuff which seals out the water - and I am now working on the boiler feed pump arrangements.

While making good what had been water damaged, there is no intention to upgrade any of the original power plant apart from the boiler, as I want it to be as I stopped work on it all those years ago, and to be as I developed and designed it as a schoolboy with no prior engineering knowledge. It all worked well and so that’s how I will complete the restoration. However, I will finish all the details of the super-structure and external fittings that were never carried out at the time. In my haste to have a working model quite a lot was not finished according to the drawings.

Twin water feed pumps were originally installed as I didn’t know how much water would be needed, and the boiler level was controlled by opening or closing a tap-type valve on the intake side of the pumps, this being drawn directly from outside the hull through a pipe soldered into the copper keel. The pumps are driven by cranks on a shaft which in turn is powered by a worm drive off the Stuart crankshaft. This has all been brought  back into working order.

I am now continuing work on the new boiler, and there will be more of the restoration of Wild Cat in Styx 9 or 29.

New boiler plate
Original power plant
Restored boiler feed pumps
Restored engine and prop shaft
Stripped down hull -

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