(Workshop member Jim Martin describes what he calls "Dead Rail’s Dimwitted Cousin"...)
|Electric turnout control, about as easy as it gets!|
As I switch over to Dead Rail (battery powered locos) - obviating the need to climb under the layout to solder feeders - I got to thinking about those Tortoise switch machines lurking beneath.
Conventional thinking would still have me climbing under the layout with a soldering iron to connect to the power bus and toggle switches. Why would I want to do that? So I’ve put into practice a method I experimented with years ago, using a small 9-volt battery as an external power source - an electronic switch key if you will.
Here’s how it works:
Quite simply, the two wires required to power the switch motor are brought out to the front of the layout fascia where they can be activated by the battery contacts. Touch for one direction - flip the battery for the other direction. I actually thought of drawing a wiring schematic for this article but that would be akin to listing the ingredients in milk. The photos are the schematic:
Ignore the wire colours. They mean nothing: I was just using up scraps of wire. The polarity is either one way or the other, and as you will soon find out, that’s really easy to change.
Tortoises are stall motors - that is, they are supposed to be under power at all time. That would require connecting them to an under-the-layout power bus. But my experiments have shown negligible creep-back once the power is removed. So I thought it might be feasible to use external battery power. As the late John Armstrong would have said, the method has been “feased”.
Most of the work can be done at the workbench. For each switch machine cut two lengths of wire and solder alligator clips to one end of each. Cut an electrical gap in a short length of printed circuit tie and solder the other ends of the wires to each side.
Glue the tie to the bottom of the facia in front of the switch points you want to control, bend the wires under the layout, and connect the alligator clips to the switch machine’s outside terminals. Don’t worry yet about which wire goes where.
Draw arrows on each side of the battery indicating point travel and start testing each switch. If the point travel is contrary to the arrow simply swap the alligator clips. That’s it for the under-the-layout work.
|A close-up of the printed circuit board tie, glue to the bottom edge of the fascia.|
As you can see, the contact points on the front of the layout are pretty unobtrusive but I’ll probably improve the cosmetics. I also plan to build a more elegant battery case, one with spring contacts and a DPDT switch to control turnout direction.
In the meantime I have an inexpensive and uncomplicated way to operate my switch machines - one that’s stoopid simple.