Switch Rods

I wrote before about my dislike of just about all the switch rods I’ve ever seen on model railways (including my own).

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The standard PC board has two things wrong with it. First, it usually doesn’t look much like the prototype, which is typically made of a flat steel bar a couple of inches wide and about half an inch thick. Now, there have been some very fine PC board switch rods that look great, but they will be even more exposed to the second problem.

The second problem with PC board switch rods is an engineering defect: as they move back and forth, the points need to pivot slightly on the board. You wouldn’t think this tiny movement was enough to matter, but it is. My friend Brian Pate, who is a wonderful modeller, seems to get his soldering iron out in about every fourth operating session; now granted he has a lot of switches, and the repair takes him only seconds because he is so very adept at holding his tongue just so, but I feel this is too often.

Proto:87 Stores offers a switch rod in which the rod is represented by two vertical pieces of etch, which move with a section of roadbed. They lock into tiny holes drilled in the foot of the rail, which allows everything to pivot properly. Gary Hinshaw uses them with great success on his layout, and if I weren’t so pig headed, I probably would have used them to.

The P4 guys, of course, use an assembly they call “droppers.” These are wires soldered to the points, which pass independently through the roadbed to connect with a throw bar beneath. The switch rods themselves are purely cosmetic. I actually drilled dropper holes in the south section as a backup, in case my switch rods fail in a few years’ time.

However, here is what I did for now.

Switch rods and throw bars

The switch rods are made together with a throw rod, which moves in a recess formed by making the second head block tie only half depth. The throw rod is sturdily connected to the clamps for the switch rods, and these are glued to the rails. The switch rods, themselves are cosmetic. The whole thing is printed in Shapeways’ “Strong White Flexible” sintered nylon, and the throw rod narrows just before the clamp section to enable it to flex slightly.

The round post at the bottom is actually a tube, and the wire from the switch machine pushes against the inside of this tube.

Switch rods and throw bars

Switch rods and throw bars

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