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Wednesday 16 September 2020

Project 20 - 0 Gauge Layout - Part 27

 I needed to isolate a couple of sidings in order to hold a loco on the layout whilst another is driven (analogue control). Those to be isolated are the middle tracks at the bottom and top of the layout shown in the photo.

The idea is to isolate the power to the bottom siding where the Terrier loco is held whilst the Class 33 and its wagons are driven from the Branch Line to the top siding. Power to the top siding is then isolated and power turned on to the bottom siding so that the Terrier can pick up the wagons and shunt them to other areas of the Quay.

I did not install the power switching at the track laying stage. I waited until after the track was buried in tarmac. There was some logic to this because all track sections are independently wired to a bus bar underneath the layout and there are no fishplates joining the sections. In theory all I had to do was disconnect a siding rail wire from the bus bar and fit a switch between the bus bar and floating wire; this being done for each of the two sidings in question.

Where to locate switches took some head scratching. The thing is, the layout can be operated from either side. A fixed control panel therefore, would not be appropriate. A control panel would need to be hand held. Furthermore, the layout is spread across two portable baseboards. This would need cabling with plug and socket between boards and an umbilical cable to the hand held controller. I went as far as making brackets for D type connectors before thinking this was going to defeat the objective of keeping electrics simple.

My final solution was to fit two switches for each siding, one to each baseboard side. The switch on the side of the layout that is not currently operated from is held off and the one on the operating side controls power to its siding.

The next issue was the decorative quayside wall. I did not want this spoiled with a thumping big toggle or push button switch. I choose a miniature sliding switch as being the most unobtrusive and instead of screw fixing it to the wall I fabricated a holding panel that is glued behind. If I ever wanted to reuse the switch I guess I could break the panel glue bond to retrieve the switch.
Switch located in line with the siding it controls.
A second parallel wired switch is located
directly opposite in the other side panel.

So far so good. With switches in place I tackled the wiring. Disconnecting the first siding wire from the bus bar I tested that the track rail was now isolated. It wasn't. Clearly the rail was touching the live rail of the next track section! How the hell was I going to resolve that now the track was nicely buried in tarmac!

I had to carefully razor saw at the rail join to break the connection which also left a saw cut in the tarmac - to be repaired. Thankfully, the rail join in the second siding was already isolated, as intended.

To Part 28.

To Part 1.

OK, why worry about a switch showing with
a large hinge in view? Good point.
(BTW. This hinge is at the non-
decorative fiddle yard end.)

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