I have a wiring problem that I need some help with. I have a tourist railroad that shares station access with the regular railroad and I need to figure out how to wire it. The main railroad is red in the included diagram. The tourist railroad is in blue (at least the section needed for this diagram). The shared section is in green. The main railroad is on cab control. The tourist railroad has its own power source and own control panel which is not hooked into the cab control system. I am unable to use snap relays, at least as I understand them, as I an not using remote switches (manual only). Does anyone have any ideas on the simplest way to solve this problem? The diagram is located at http://www.ccrvfc.org/PTTX_FRRY Interchange.tif in case the image hasn't loaded.
You can use a double-pole, double-throw toggle switch to do this. The center posts go to the shared track, and the outer posts go to the feeders from each of the control systems.
Note that I italicized can. I'm not a big fan of this kind of wiring, because it depends on everyone doing the right thing, and the result of a single mistake could be serious. Depending on the systems involved, you could burn out all sorts of expensive equipment if the toggle is thrown the wrong way when a train enters the section. You would end up connecting the two control systems to each other when the train bridges the gaps.
As for the image - it may be that the embedded blank doesn't work, or maybe the img tag just doesn't like .tif files. I don't know.
It takes an iron man to play with a toy iron horse.
The trick to making that DPDT toggle (or slide) switch foolproof is to have it move with the points - mechanically linked together. Then, when the points are thrown for mainline access the mainline cab controls. Throwing the points to favor the Turista connects the rails to that separated supply. There have been several threads which included a variety of methods for connecting mechanical actuators to electrical switches as well as points.
In my own modeling, I have the reverse situation. The toggle switch IS the ground throw (but mounted in a niche in the fascia, not on the layout surface.) The usual connection to the switch points is monofilament fishing line, with a weight on the far end to pull the points to the less-favored position when the toggle is pushed toward the layout instead of pulled toward the aisleway.
Chuck (modeling Central Japan in September, 1964)
I just relized that I neglected to mention that the planned shared block (the green one) is electrically isolated as part of the cab control system already so that I can park an engine on the siding. I don't know if this would complicate or simplify the wiring.
Is there a reason not to put the tourist train under cab control like the rest of the railroad? In the long run, that may be your best solution. With any of these dual-power options, you still run the risk of overrunning the isolated area, or forgetting to throw either the turnout or the controlling toggle. Better yet, DCC would make all of this unnecessary.
You might consider getting one Tortoise machine and installing it to control the critical turnout. The Tortoise comes with a double-pole, double-throw set of contacts, which would provide automatic setting of the power selection for that track section.
The main reason why I didn't put the tourist line under cab control is I intended for that block to be completely on its own power supply so that it doesn't draw from the other packs. Basically I wanted to create a local control panel.) Secondly, the block for the tourist line also has a reverse loop in it for turning the train. This is intended to be the end (or begining, however you wish to look at it) of the tourist line. I didn't want to try to wire that into the cab control (would need another controller (1 is backup for turntable drive on another part of layout.))
As for the DCC option, some of my engines (especially the steamers [Model Power 2-6-0s] on the tourist railroad) are small enough that I don't see how I would fit a decoder in them. Secondly, I can't justify the expense of DCC to myself. (I have a number of engines and would need a decoder for each of them.)
Are there fourms that I could use to tell me on the use and hookup for a Tortoise machine, especially for this purpose? (I have never used or even seen one!) Am I correct then in presuming with a Tortoise machine that when the turnout is actuated the power will route correctly? (In other words, if the turnout is aligned for the tourist line, it will power the station block from the tourist pack. And if the turnout is aligned to get back on the mainline the mainline pack(s) will power it.)
Thank you for all your assistance with all my requests.