Sunday, 7 July 2019

July 2019 meeting

Our July meeting took place a week earlier than usual. Andy, Jim, Alisdair and Alistair met at Graham's house in Edinburgh. One subject of discussion was last weekend's Perth exhibition put on by the Scottish Model Engineering Trust, where the FCAG (pictured, Jim and Nigel) manned the 2mmSA's Further North roadshow.

Thanks to the Perth club for inviting us. We enjoyed the show which had a subtly different flavour this year, with a diverse range of prototypes and scales and a consistent standard of layouts.

But back to our July meeting. The Short Talk was by Jim, expounding on how to file up turnout switches and crossings with jigs. Or at least, that was his original intention, but he ended up talking us through the whole Watt Way of turnout construction.

Jim has written up his methods extensively in the 2mmSA magazine, and the Association's Track book (available to non-members for online purchase here) is another valuable reference. I won't give more than a summary here. It's well worth reading (or re-reading) Jim's articles mentioned below. (The magazine archive is available to Association members on a USB stick as part P-109 from Shop 1).

Jim models late-1890s Caledonian Railway practice, so bullhead rail, interlaced timbering and loose-heeled switches are the order of the day. His article in the August 2012 magazine covered the construction process. He lays out the turnout on a Templot plan, starting with the four interlaced sleepers in each road of the crossing which carry the crossing itself and the check rails. The tip of the crossing's point rail must sit on a main road timber so this is positioned first, then the others added. Next, the two close-spaced timbers which anchor the switches (at the opposite end of the closure rails from the crossing) are positioned. Then interlaced timbers are laid by eye between these two, starting with a sleeper on the main road and proceeding towards the crossing. (Templot can produce a template showing these by shoving timbers, but this lengthy process is not really necessary in 2mm scale).

The switch rails are aligned with the closure rails with little fishplates made from copper shim, bent into a "U" formed in a jig (slot sawed in a piece of brass strip of rail thickness). The fishplate must be no longer than the space between two sleepers. It is threaded onto the switch rail and squeezed gently into the rail web using tweezers, then slid along so it projects half-way off the rail end and soldered. The fishplate can then be slipped onto the closure rail, but is not soldered: it is prevented from falling out by the tiebar mechanism which holds the switch rails in place vertically and horizontally.

Jim's tiebar design was written up in the December 2008 magazine. The tiebar is formed in two parts from wire bent up in a small jig made from a sandwich of three brass plates, one with sawcuts of precise widths and depths to receive the wire at various stages of bending, the other two on either side to stop the wire moving from a vertical plane. Very easy to make with hand tools and very effective. We were shown the jig and the wires.


Once installed the tiebar looks very neat, and the arrangements under the baseboard are equally straightforward. In his demonstration model shown here Jim deliberately left the through-baseboard pivot exposed so it can be seen, but on a layout this would be hidden by a ballasted slip of paper with a slit for the wires, which then look very much like a prototype tiebar.

Jim also described his memory wire point actuators, which have the advantage of silent operation compared to solenoids or servos. The February 2013 magazine gives further details. 

Switch rails and crossing point and splice rails are filed up from bullhead rail using a Geoff Jones hinge jig. Jim described how he made the 0.030" brass profile plates in the August 2012 magazine. The hinge is steel. He showed us the jig.

Jim's original ballast recipe was 1:1:3 Cascamite:Plaster-of-Paris:fine sand, with poster paint added for colouring. There was some doubt whether Cascamite (a powdered-resin wood glue) is still available, but a quick check on trhe Internet shows several sources online. More recently Jim has used crushed cat litter. If this is done carefully, the cat can be straightened out and re-used.

At that point we paused for a feed. Bacon rolls, cake, tea and coffee were consumed, then it was back to work. Andy was fiddling with wagons on his test track while Jim progressed with the second footbridge for the Grampian area group's Dunallander layout - he received the bridge columns at the Perth show from Roy Bremner, fresh from his lathe. Turning the thin columns required a bit of experimentation but ultimately Roy got the knack of it.

Alisdair was working on adjusting the Electra couplings on his stock for consistent operation, so had brought along his portable test-track/cameo Aye for that purpose. The two parts bolt together for transit:
then are separated: 

and joined using flight-case over-centre catches. Very neat.

After much tweaking of couplings and noting down of wagon numbers "Not to Go" with defects, Alisdair pronounced himself satisfied. The loco assigned to the coupling test duty was his Caley "Jumbo", 57232:

Graham contemplated his LNER fish van chassis collection, which has been growing at the rate of three or four chassis a month. At some point, buffers, wheels, couplings and paint will be required. And the bodies (Foxhunter kits) of course!

The August meeting will probably be in the West, with details to be sent out by Alisdair as usual once venue and date are confirmed.

No comments:

Post a Comment