Hi! It has been about seven years since I last wired up a reverse loop on a model railroad that I built. At that time I used a lot of the Atlas selectors for the reverse loop. Now with a new railroad that I am building I want to be able to use the switches (ex.SPDT ) that I could pick up at Radio Shack. Does anyone know what kind of switch I would need for a reverse loop so that I could avoid polarity problems. I would be open for any suggestions on how to wire this. Thanks in advance! -Tony
I stay away from reverse loops whenever I can, but I did wire a friend's layout which has one, and am sure I used a DPDT switch to power an isolated part of the loop, where the trains come to a stand anyway. Really needs a drawing to explain properly. Does anyone have one available please?
That's a pretty complicated system for handling a simple reverse loop Paul! Why do you need two transformers? I am assuming of course that a controller is a transformer in the UK. Show us a drawing of this system hooked up to a track plan with a reverse loop in it. My swyd has three blocks and to the latest computation, about 441 reverse loops in it and it is all handled by three DPDT switches and one transformer, controller? Seriously!
Allan. I think you experienced guys are pulling our legs, asking for someone to send in a drawing of how to wire up a reverse loop DPDT switch. However, if you are interested I'll send you an operating track plan of my switchyard with the three blocks and the seven 441 reverse loops in it, and show how simply it is wired and also a drawing of how to wire up a single reverse loop using one transformer and one DPDT switch. Operating in this switchyard full of reverse loops was not a simple matter however, but it has been handled using a Block Polarity Monitoring Signal System, that I designed to fit under my Kato Unitrack. The circuitry is hidden under the Unitrack roadbed and becomes a part of the track module or Unitrack turnout module, as I also use a similar light system at my mainline switches to show which way the turnout is thrown. It is a plug and play system with no external wiring required and draws its' operating power from the tracks. I can send you photos of it all if you would like. Hope you are interested, Kato sure wasn't. maybe Atlas or Peco would be.
Here is the circuit that I used on my layout, it basically uses a bridge rectifier. the only downside is you cant reverse direction while on this section. You can visit my website for more information
Hi, They are not transformers, they are the throttle controllers that move the train, this way you have the option of either controller (A or B) to run the train into the reverse loop and out, in any direction. [ 02 June 2002, 16:52: Message edited by: Paul Templar ]
When I had my layout with reversing loop, I used a Tech ll with two throttle controls. They were hooked up just the way Pauls drawing is. Operating on throttle 1, when the train started into the loop, I made sure the polarity of the loop was the same as the main line. Once the engine cleared the insulated joint I reversed the polarity on throttle 2 and when the train came off the loop it kept right on going without stopping.
Actually, if you wire in a DPDT reversing switch between the bridge rectifier and the track you will have a way of reversing in case of unusual circumstances. I would leave the switch set one way and only use it when absolutely necessary.
Superheater, send us a diagram of how you handle a reverse loop with only one DPDT switch. I'm really interested.
Use the bridge rectifier circuit and remember to throw the direction switch on your controller while the train is in the loop. Also, if you use a spring switch you won't even have to throw the turnout.
A professor of Electrical Engineering talking to our Electrical Design Dept Staff, told us that a Camel was a Horse designed by a committee. He further added that if you really want to complicate your design, form a design committee. I think that same committee is at work here on this problem of how to handle a reverse loop. There are dozens of ways to solve the problem of a reverse loop and probably all of the systems mentioned here will work to some extent satisfactorily. Some take a lot of unecessary equipment and wiring and in some solutions you can't reverse the engine, some need multiple controllers and some need bridge rectifiers. All you really need is one transformer, a block zone and two DPDT switches, what can be simpler than that. Unless of course you find it too much trouble to put a block zone into your track ahead of the turnout that returns you from the loop. If Trainboard ever gets a picture posting system for us guys without web sites I'll send in a simple diagram of how to handle a reverse loop and also some pictures of the reverse loop polarity monitoring signal system I designed for my reverse loop nightmare layout.
A professor of Electrical Engineering talking to our Electrical Design Dept Staff, told us that a Camel was a Horse designed by a committee. He further added that if you really want to complicate your design, form a design committee. I think that same committee is at work here on this problem of how to handle a reverse loop. There are dozens of ways to solve the problem of a reverse loop and probably all of the systems mentioned here will work to some extent satisfactorily. Some take a lot of unecessary equipment and wiring and in some solutions you can't reverse the engine, some need multiple controllers and some need bridge rectifiers. All you really need is one transformer, a block zone and two DPDT switches, what can be simpler than that. Unless of course you find it too much trouble to put a block zone into your track ahead of the turnout that returns you from the loop. If Trainboard ever gets a picture posting system for us guys without web sites I'll send in a simple diagram of how to handle a reverse loop and also some pictures of the reverse loop polarity monitoring signal system I designed for my reverse loop nightmare layout.
Gary, send me your schematic attached to an email and I'll post it here for you. I am an electrical engineer.
FITZ, thanks, I just saw your reply today, I will send a diagram of how I handle my reverse loops and photos of the track signal systems I designed for monitoring block polarity and turnout indication. Thanks Gary
Actually the diagram is probably simpler than the explanantion. In the diagram, pick the rail at the word TRACK that has the red wire connected to it and follow it around with your finger. When you get back to the word TRACK, you'll find that you are on the rail connected to the green wire. So you have a reversing problem. That is what the ISOLATED BLOCKS are for, to change polarity! When your engine ( or finger ) is in BLOCK B, on the red wire rail, you throw the DPDT switch in BLOCK A and it transfers the positive feed ( red wire ) in BLOCK A , to the rail the green wire runs to. This allows you to change isolated BLOCK A to the same polarity as in BLOCK B that you are currently running in. I also use a diode matrix that monitors the polarity at the end of each of my blocks and it tells me via red and green lights on a two lightboard tower if the polarity is matched at opposing blocks. Green matched, red not.
