Turntable Indexing Started

Andrew came over on Wednesday and we made a start on indexing and feeding the staging yard turntable. This more or less followed the original plan from October. I varied the plan by using square brass rod and tube because it’s easier to solder things that don’t want to roll away from you. I also decided not to mount each pair of shore-side connections on their own PC board because I envisioned the screws working loose over time and indexing becoming less and less accurate.

While Andrew started preparing one of the off-cuts from the turntable top to serve as a base for all the shore-side connections, I drilled and tapped some holes in the turntable to stop the PC-board top from floating around so much. When I screwed the screws in, it produced a dead short. I’m embarrassed to say how much head-scratching it took to figure out what was going on, but in my own defense, I hadn’t checked the electrical continuity of the turntable in a while, and there were a number of gaps that could have been bridged accidentally.

Meanwhile, Andrew had prepared the base for the shore-side connections, including adding a piece of wood into the bus trench to support the base. The base is 2-sided PC board, and the bottom carries electricity to all eight connections (four tracks, two rails each). These buses are connected to the top by short wires, and the ends of the wires were filed almost flush so they don’t look too messy on the top and so the base sits flat on the bottom.

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I cut the gaps between the tracks last night, but left the gaps between the two rails of the same track until at least one tube of each shore connection was soldered in place. This way, I didn’t have to be careful about locating the gaps in exactly the right place.

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Finally, tonight I soldered one side of everything in place. This effectively indexes one end of the table and feeds one rail. While it took longer than I expected, it seems like the plan is going to work.

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