Because the railway is power zoned, there are several track buses - not just one. Each zone has its own common return wire for the "blue" rail; the "red" rail is fed from the relevant block detector output. This means a lot more wiring than for non-block detection DCC wiring, even with the block detectors fairly well distributed around the railway. This is essential for computer controlled operation; it means that a short in one area will not prevent trains running in another. Ultimately the wiring has taken a little longer, but it isn't difficult and it is still easy to follow. However, an accurate record of "what is connected to where" is essential. When planning the block detection, I developed several spreadsheets that show what track section is in which power zone and which block detector provides the power.

The common return wires are 0.75mm2 24 strand copper wire. These can see a maximum current of 2.5A, because of the power zoning. The feeds to each detected block are mostly 0.5mm2 copper wire; except when there is a short, these will only see perhaps 0.2A because there will only be one train in each section. Each is still rated (and tested) for the full 2.5A "short circuit" current.

The droppers from the track sections are joined to the bus power feeds using crimp "bullet" style connectors. The dropper wires have a male bullet crimped to them. The "red" wires are fed directly from the block detector boards, arriving ultimately at a female bullet connector. The blue (or sometimes black, where I ran out) return wire feeds a "daisy chain" of female bullet connectors. I found it very easy from under the railway to run a wire to the next position, and have two wires crimped into the bullet connectors.

I had intended to use "Scotchlock" suitcase-type crimp connectors to make the tap-off joins onto the main bus runs. There are a few used in places. However I found that daisy chaining the crimp connectors was easier, in the end. I also struggled to find these connectors that were specified to work with the cable sizes I'm using; while they may work over a wider range of wire sizes, the "specified" sizes that the manufacturer guarantees are quite restrictive.

Point Frogs

Point frogs get power from the switch built into the SEEP point motors. The track bus is wired to the point motor, and the frog is powered by the sliding contact.

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