Monday, February 14, 2011

Emsingen Underground

True, I didn't put up photos with my last two trains posts. I figured nobody is reading this stuff anyways. I was wrong. So, by popular demand this post goes into a few more details, and has photos of the ugly underbelly.

Emsingen Underground
South Switches from below
For orientation around Emsingen, take a look at the photos in this post from last year. The small yard in the upper photo is at the south end of Emsingen, while the north side sports a loading ramp, and a tail track.

Most people don't show the underside of their layouts because unless you have a large layout, or are really anal about cabling, it's usually a mess. Exceptions confirm the norm. Modular, or portable layouts tend to have cleaner cabling than stationary layouts. Anyways, the photo on the right gives a pretty good idea what my cabling looks like... Hey, at least I color code everything. Black/red is the main DCC bus (usually AWG14 cable). I have three independent power districts, this is in the "blue" district as signified by the blue tape wrapped around the bus cable.
Those red plastic thingies are 3M insulation displacement connectors (IDCs) to connect rail feeders to the main bus. The round grey cables are various local cable runs (e.g. the one at the top is connected to train detection sections, the one at the bottom runs to a servo in a somewhat remote corner of the layout). Blue/yellow is the 16V AC bus, and blue/red is the DCC accessory bus.
The printed circuit board in the back is a Tam Valley Depot QuadP servo controller.

The photo below shows my technique for installing and  connecting Tortoise switch machines. First off, at the workbench, I solder a short cable to the contacts and run it to a terminal block. The Tortoise has two built-in contacts for powering frogs or switch feedback. I don't really have a need for either of them, but since I have a 5 wire cable, I connected one of them.
Emsingen Underground Yard Switches
The Tortoise is screwed to a block of 3/4" plywood. After I prepared the hole for the throw bar at the switch, I add some wood glue to the top of the block, thread the actuator throw the hole in the switch throwbar, position the Tortoise, and test the throw, repositioning the motor until I found a position that evenly throws the switch without going too far in either direction. Then I hold the motor in that position until the glue starts to set and becomes tacky.
Depending on the amount of glue I added, this takes anywhere from 5-10 minutes, which is usually enough working time to find a good working position for the motor, and not so long that my arm falls off before the glue has become tacky enough to hold the motor in place.

Using terminal blocks between the track and the main bus, or between switches and decoders, makes it easy to disconnect wires for debugging.

Tortoise vs. UP5
Sometimes things don't quite work out, because you don't think about what happens behind the scenes. A few weeks ago I installed a Digitrax UP5 panel in the fascia at Emsingen. This is used to plug in Loconet throttles. The panel is connected to a printed circuit board that extends a couple inches behind the fascia. No problem. ... Until I tried to install the Tortoise for one of the yard switches, which happens to collide with one of the Loconet plugs at the back of the UP5. Had I installed the UP5 half an inch to the left, or a couple inches to the right, this would not have been a problem at all. Now it just barely fits when I let the UP5 stick out from the fascia a fraction of an inch.

Emsingen North Switches from below
The photo on the left gives an idea about how cramped the area underneath Emsingen is (and how big those Tortoise motors are...) Not only is there plenty of cabling in the way, but also a track running through the middle of it. Those white "guard rails" are extra slats from window blinds.

Emsingen South Switches

To wrap up, here are the south switches in Emsingen from the top. The big rectangular holes will hold the twin-coil semaphor machines ... Unless I'm crazy enough to either buy new semaphors with servo drives, or outfit the semaphores I have with servos...

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