Wiring a Crossing

[Anonymous]

Need instructions and illustrations to wire a Tomalco 19 degree crossing fo DCC operation. Code 100 rail, S scale, mounted on wooden ties.
Thanks,
Bear

[Anonymous]

wfholdefer,

Is your crossing all metal? As in, is it just as if it was handlaid?

Welcome to the forum. This place is great!

I've been researching wiring crossings myself, and I believe it depends on how exactly it's setup in your trackplan.

I *believe*, Ideally, it would be run in such a way that one of the tracks is dead while the other is powered. This could be accomplished by "deadening" the track it's on by determinining whether the track is *alive* or not with a switch hooked up to a turnout that allows the train to get onto the crossing.

I know, that's not a complete answer, as I'm in the process of figuring it out myself. But with any luck, at least I've offered some food for thought...

I believe many of the commercial turnouts with plastic components in them are cleverly designed in such a way that there is plastic in the critical "shorting spots". With handlaid track, things get trickier...

[cacole]

I'm not familiar at all with the brand of crossing diamond you have, but if you have a Volt-Ohm-Milliameter with a tone generator for tracing wiring, it's easy to determine how the thing is wired.

Touch one probe to a rail at one end, and the other probe to all of the other rails around the diamond. If the only tone you get is when you touch the probe to the rail that is exactly opposite to the first probe, the diamond is properly insulated and nothing more should be necessary. If you get a tone on more than one other rail, that diamond is going to require insulated rail joiners at one end, possibly on all of the rails but usually necessary only on the rails that diverge from the frog.

If you don't already own a meter, they can be found at Wal-mart and other stores for as little at $5.

[BR60103]

A lot of what you need to do depends on the rest of the track formation.
Designate the rails N and S for your wiring (what would be called polarity in DC) and trace them around. You should find a pair of N rails coming together at one frog - either the acute frog or the obtuse frog. Two S rails should meet at its opposite number. The other frogs will have an N and an S rail meeting.
The NS frogs should be isolated from the rest of the layout -- 4 gaps. Hook a DCC reversing module to these frogs and to the power bus. This gives automatic operation.
You could use a DPDT switch instead, but that requires action every time a train comes across. In some situations you could wire it to contacts on a switch machine.
I think this was covered in Model Railroader earlier this year.

[rolleiman]

This is actually a double crossover but you can view just the crossing part of it and get your information.. Wherever you see red and blue cross, needs to be isolated. Then install jumpers past the isolation points.. If you want the isolated frogs to be powered you are going to have to come up with a routing scheme.. If you are entering your crossing via turnouts and using machines with contacts (tortise or similar), it's pretty simple.

[image]http://www.rolleiman.com/trains/double.jpg[/image]

Jeff

[Anonymous]

A good start for my first encounter with the forum.Thanks for all your suggestions. I think I can devise a workable wiring system.

[Anonymous]

Alright,

I've been working on this myself. Here is how I'm planning on wiring a handmade crossing for DCC. Note the use of a double pole, double throw (DPDT) switch that will be used to select the route. My understanding is a DCC autoreversing unit could be used in its place.

the pics show "neutral", as well as each route being selected.