0-16.5 scale narrow gauge (2'6") american Shay locomotiv by caderifor

Last crawled date: 3 years ago

DO NOT BUILD THIS THING ! READ THIS FIRST
Having nearly completed the locomotive, apart from the representation of the drive train,
I have just discovered that I got my drawings confused and used one that is only 82% of the desired size.
I do not plan to start again and I may just replace the cab so that I don't have to saw off the driver's legs.
I have redone the design with the cab rescaled.
This design is an attempt to produce a 7mm / foot Shay articulated locomotive using the chassis / mechanism of a Hornby BO BO diesel (BR class 29). The Hornby mechanism, being entirely on one bogie, is positioned in the bunker. The model is based on a drawing of Santa Barbara pole and rails logging loco, found on the internet. But I have opted for a 2 cylinder engine with eccentric valve gear in the centre section. (2 eccentrics sandwiching the final drive gear from the motor/gearbox)
The top of the box hiding the engine, in the cab, has been removed to save having to remove a large block of support. So it will need replacing with plastic card or similar.
The lamps I have included are designed to accept white LEDs. and there is a hole for thin wires through the smokebox.
The biggest snag for authenticity is the wheelbase of the bogies. The Hornby frames (powered and unpowered bogies) are replaced with printed truck frames, incorporating the driveshaft fittings. I have reversed the motor bogie to lessen its intrusion into the cab, and so I have reversed the axles in the front truck for pick up purposes.
The big modelling challenge is the working (at least apparently working) engine and driveshafts. The plan is to assemble a crankshaft of printed crank webs joined by brass tube sections forming big end and small end, with the crankshaft running in brass tube bearings in the engine frame. Although I have started trying to fabricate the crankshaft in brass..
The bevel gears on the driveshaft are conveniently hidden and not modelled, but the mating gears on the wheels are visible so are represented by printed gears stuck to the appropriate wheels.
This leaves the universal joints and extendable jackshaft, that I will post once they are more than an idea. These are unlikely to be printed items.
I have purchased a small 200RPM motor/gearbox and a bag of assorted gears to drive the engine and drive train and I hope the difference in start voltage between this and the traction motor is not too obvious.