Sunday, 7 December 2014

HR 54 Yankee Tank; detailing the engine

HR54 chassis with cylinder detail.

Beneath the cylinders, the cylinder drain cocks (three on each side), await the fitting of the centre unit to make a trio. Each cock is made from a small hand rail knob soldered into a hole in the cylinder bottom behind which a short arm is held in place by means of a pin through the hole in the knob. The arms support the pull-rod which is attached at its further end to a lever below the slide bar support bracket which is about all that can be made out of the mechanism from the drawing and existing photographs though I think there's probably an operating rod attached to the latter lever leading inboard.

Yankee Tank chassis with brake cylinder under cab.

The brake cylinder under the cab is cut away to clear the shaft of the rear coupling hook. Despite scrutinising the drawing I can't understand how the linkages to the brake cross shafts are arranged. Photos don't help clarify the matter as this area is masked by steps and sand boxes. Now that the inside motion has been removed and the driving axle changed from the rear axle to front one I have space in the firebox below the motor for extra weight, in exactly the right place, between the driving wheels. One of the 3ft driving wheel springs which are my own w/m castings is in position below the front right hand driving axle bearing.

HR54 superstructure progressing.

The Roscoe Lubricators on the smokebox sides are brass castings from LGM (ref: 19-35). Slaters' Hand Rail Knobs (S) proved to be just the right size for the cab doorways and tank sides, apart from these knobs all other linkages on view are scratch built. Visual evidence suggests that there was only a sand box operating mechanism on one side of the engine, I'd be interested to know how in this case the right hand sand box worked. Photographs show that the large cab roof was not devoid of interest as it had four thin metal strips riveted across it and, though I've not managed the rivets, I think the cross-strips work well. There's another lamp iron to add when it arrives from Laurie Griffin and also a handrail towards the rear of the roof; photographic evidence, though leaving no doubt as to its existence, is tantalisingly imprecise regarding its exact position.

HR54 showing cab interior.

I have left the cab until last; there is little precise information available for the cab interior of the Yankee Tanks, nevertheless I think the cab will be a busy place eventually. There are rods and pipes protruding in profusion into the cab through the spectacle plate that need handles knobs and terminating points, there are pressure gauges to fit, a reversing lever and hand brake stanchion and all the pipework and oddments that go to make up the backhead itself. The hollow backhead houses the fly-wheel now that the motor has been repositioned and can still be removed at this stage which will help while completing the cab interior.
I've made a master pattern for the tank top water fillers but have not yet made a mould or cast them, this is a job for next week. Any other modellers who would like a pair of these for their own Yankee Tank project should just let me know, they'll be available very soon.