THE SIGNALHILL RAILWAY
(It could also be called The Stony Hill Railway)
The S.H.R. is a miniature railway. Built by me with the valuable help of friends and members of the Otago Model Engineers
It is situated on Signal Hill road just below the Signal Hill lookout in Dunedin at a height of a little over 1000 ft.
I started some 6 or 7 years back and planned the track with the help of a club member. It is now in the configuration of a dog bone, but with both return loops folded back over each other in to one return loop, as opposed to two. With this arrangement to do a full circuit, the layout is traversed in both directions thus doubling the track length from 540 m to 1080 m.
The track gauge is dual 7.25"and 5", with a ruling grade of 1:80. The maximum rise and fall in the track is 1.80m with minimum radius curves of 15 m.
The track is constructed out of 25 x 10 mm. flat steel inserted into slotted 50 x 50 mm. tanalised 400 mm. long sleepers.
There are seven points made with chairs bolted to the sleepers, to accommodate the moving switchblades. The point blades are spring loaded.
Loco and wagon wheels open the trailing point blades.
The railway can be set up in five different configurations. The most popular is the full double run of 1080m.
Because of the return loops, head-on collisions are a distinct possibility.
I came across a simple system in an old issue of American "Modeltech"magazine, This uses only three wires for each block. We have two blocks.
This system uses only two lights, amber and red. When the block is unoccupied there are no lights showing
When a driver wants to go through this block. He or she presses a button next to the track and gets the amber light, this is his (hers) track warrant,
The light on the other end of the block will now be red. When arriving at the other end the driver now has to reset (cancel) the lights by pushing a button on the side of the track.
Again there will now be no lights showing, so the block can be used by whoever is first from either direction.
Because of the return loops the 5"track created a problem, however this was sorted easily by a couple of fixed transfer rails.
The S.H.R. has a railway station (but no station building as yet). an engine shed , a turntable, two steaming up bays, and approx. 40 m. of auxiliary track,
There is a 20 m. curved tunnel, and a 50 m. curved trestle .At its lowest point the ground falls away about 3.5m, plus cuttings and embankments.
Plans are being worked on for a 7.25" only extension. This will take another year or so, before it will be finished.
March 06 John Rappard