Sophisticated Reverse Loop Wiring
Automation Using LGB Components
BY TED GREENO
TOM GUENTHER, FROM Mentor, Ohio has built "The Guenthers' Backyard Baltimore & Ohio Gazebo Railroad" completely on elevated track. Tom loves woodworking so his railroad has every kind of bridge imaginable and bridges are everywhere. Since, as you might guess, Tom also loves the B&O, everything on the layout either has B&O markings out-of-the-box or will have them in very short order after his wife gets through with it.
None of that has any bearing on the article so I suppose I should address that subject now: Tom had trouble wiring a reversing loop. His layout consists of a single track mainline with a reversing loop at each end. Wiring two loops was straightforward but, when Tom decided to add a third reversing loop and also use LGB components, he came to me for help.
Look at Figure 1 and you'll see why. Tom wants to run from Loop 1 to Loop 2, then back to Loop 1 and onto Loop 3. He wants the cycle to repeat and, of course, he wants everything to be automatic so he may sip iced tea in the evening completely undisturbed. [A noble and understandable aspiration.-Ed.]
Figure 2 illustrates the solution. We have added three LGB 1700 track contacts, a remote 1201 EPL switch drive, and the associated 1203 supplementary switch for an EPL drive. It was necessary to add switch P to allow the train to move between Loop 2 and Loop 3. The wiring between 1700s X and Y to the remote 1201 is normal, but from there on it departs from what you might expect.
The 1700 Z has no way of knowing how to throw switch P when the engine carrying the 1701 switch magnet runs over it. It has no way to determine what lead from the upward or downward pointing triangle will connect to the 1201 on switch P. The remote 1203 controls that. Incidentally, I tested the wiring on a demo board before suggesting it to Tom.
One more little gem of information: If your LGB turnouts operate poorly, you should realize you are pushing the capabilities of a 1201 to its limit if you ask it to operate a turnout as well as a 1203. Almost anything, especially dust and dirt, will cause the 1201 to fail periodically. You may correct the problem by using a 24 volt a.c. doorbell transformer instead of the 16 or 18 volt accessory terminals on your power pack.
You may buy a doorbell transformer at any hardware store. It typically will cost between four and seven dollars. If you still experience problems, add another 1201 as in Figure 3. Unless a small foreign object is floating around your switch points, the additional 1201 will solve the problem once and for all.
If you want to ask Tom about wiring a third reverse loop, write to him at 6235 Cedarwood, Mentor, OH 44060. By the time he has completed the addition to his mainline, he will be a reversing loop wizard!
