reverse loop meltdown

Model Railroader General Discussion (Model Railroader)
1

A little help please! I’m new to this 2 rail stuff. When modeling the reverse loop,does the entire lenght of the train have to come to a complete stop in the isolated block before you flip the reverse loop switch located on the power pack? The atlas manual has relays & all sorts of gagets to complete the wiring. How did the guys 25 years ago wire the loop,before all this fancy stuff came out??? Thanks Easter

2

You need one of these, An Atlas #220 Controller

http://www.atlasrr.com/Images/Track/Trackphotos/220.gif

Jim

3

In DC, you need a separate Double-Pole, Double-Throw (DPDT) switch control for the reverse loop. You don’t need to stop the train, but you need to match the polarity, which in DC is the same as the direction of travel, between the main line and the loop. While the train is in the loop, you flip the direction switch for the main line, because the train will be going the opposite way when you come out.

An Atlas “Twin” contains two DPDT switches. If you wire one of these to your main line, and the other to the loop, that’s really all you need.

In DCC, it’s basically the same thing with one operational difference, and one very important simplification. Once the train enters the loop, you flip the DPDT switch for the loop, not the main line. Here, you’re flipping the polarity of the signal, but the direction of the train remains the same.

In DCC, it’s really worth it to invest in an automatic reversing module, such as the PS-Rev from Tony’s Trains. (Yes, that’s a recommendation. Good product.) This replaces the manual DPDT switch for the loop. The electronics on the board will automatically sense the polarity of both the main line and the loop when your engine crosses the insulated gap between them, and adjusts the loop polarity accordingly. It will do the same on the other end when the engine leaves the loop. Pretty soon, you’ll forget all about it and just run the trains, which is what DCC is all about anyway.

4

The entire train does not need to be in the reverse loop when you throw the switch.

But, if you are running an entire train of lighted brass passenger cars with track pickup in each car… Then it might be a good idea.

The problem is if you have a long train in both blocks, and the train has power pickups, or even just metal trucks, you could have a short.

Here is one VERY simple way to make a reverse loop:

(This works only works on insulated frog, route selective turnouts like Peco)

(I don’t know of any other turnouts that are both route selective AND have insulated frogs)

Use one Peco Insulfrog turnout. Have the diverging track route around in a reverse lopp back into the same turnout.

When the train is half way around the loop:

  1. Stop the train

  2. throw the turnout

  3. reverse the direction on your power pack

  4. start the train moving again

No fancy switches required. The only disadvantage is you have to stop the train.

5

Great information guys! Thanks so much,Easter