Other than the two obvious turnouts needed for a reversing loop, what other components, both mechanical and electrical are needed and how are they used? Is there such a thing as a poor man’s bare bones setup and an all the whistles and bells loop?
Jarrell
it depends on weather you’re using DC or DCC; with eithre, you can wire up a switch for it, and with DCC you can get an automatic thing, I don’t have either, so I can’t give you any details.
the most bare bones polarity reverse is by using a DP/DT switch wired in to a block. criss cross the wires to the terminal and reverse the polarity while the train is in the loop. for a few dollars more there are all sorts of ways to reverse the polarity which include, infra red detection, train detection devises, or you can wire up a tortoise machine to reverse the polarity when you throw the switch connected to a relay that reverses the polarity when the turnout is throw if you’re using DC. For DCC you can install a reversing unit built exclusively for DCC or even use a DCC power booster to reverse the polarity. (I believe digitrax has the ability to reverse the polarity using the power booster if it’s wired a certain way.)
Jarrell,
If you are asking about DCC then I might suggest that you read up on Wiring for DCC, a great primer on track wiring, also in Part II is a section on Reversing Sections.
Allan Gartner does a much better job of explaining than I could ever hope to match.
Cheers,
Ryan
Sorry I forgot to mention I’m using DCC. Thanks for the replies so far. Is this auto thing using a tortoise fairly easy to wire up IF your main line, where the reversing section would be, is up on extruded foam 5 inches above your benchwork? The benchwork on this section is 1/2 plywood.
Jarrell
You need to isolate both tracks about two length of a locomotive in the loop. That isolated track will be feed via a reverse loop circuit. That circuit will simply detect a shortcut and throw a DPDT (dual pole, dual throw switch) to reverse the isolated track.
That’s all. Very easy to install and operate. e.g. at Walthers: 500-AD520 Digital Command Control Accessories – Auto Reverse Loop Module
my club is using digitrax super cheif and i just installed a digitrax reversing module into a wye that had been controlled with toggle switches. the module connects to the dcc buss with two wires then two wires go to the section to be reversed. it works great. a loco can enter or leave the wye from any direction without having to throw any toggles or worry about other trains on the main.
JaRRell, what loop would this be? Technically, you only need one turnout to form a loop. The loop is formed by leaving one of the two routes beyond the frog and then doubling back to the other route on the turnout. [%-)]
-Crandell
This is a digitrax auto reverser. 
how to wire one 
They aren’t very expensive and is used for reversing loops. Tony’s train exchange has better ones than the one made by digitrax. do a search there and you’ll find what you need
Oh, and I forgot to add this photo. This is the Digitrax PM42 which can be configured for 4 separate sections of circuit breaker and/or auto-reversing.
This is my first PM42 installation with 2 auto-reversing sections and 2 circuit breaker sections.
There was an article in MR on how to do this automatically (i.e. hands-free turning with a loop and DCC). I can’t remember what issue it was in, but it is available online by clicking HERE. I thought this looked like a pretty cool way to do a reversing loop. Has anyone done this?
FT
I have a Digitrax Chief (DCS-100) and have purchased two Digitrax Boosters (DB-150). I use the booster units for the auto reversing function. It also gives me additional power for the layout, which is the primary reason that I purchased the booster units.
JIM
i use an automatic control from Tony’s. ( check ad in MRR ) It also acts as a circuit breaker. When the unit detects a short, which will happen when you enter a reversing loop or track, it automatically switches polarity. If the short is still there, as if someone laid a screwdriver across the tracks, it shuts the power down. It has indicator LEDs & solder lugs to install remote ones. when the polarity is normal the green LED lights, when the polarity is reversed , as when the train enters the reversing loop, the red LED lights until the train is out of the loop & then it returns to green. Fool proof would recommend it highly. Jerry
I also use a Tony’s reverser unit. Unlike some of the others, it’s all solid-state switching technology, so there are no slow relays to worry about. Relays can have a noticeable switching delay, which might stall and reset your locomotive, and they’re also a bit less reliable than solid state.
Make the insulated part of the loop as long as you can. You really want it to be longer than the longest train that will run through it. Yes, the absolute requirement is longer than the longest engine, but then you have to worry about the engine crossing one end while any other car with metal wheels crosses the other.
I’ll admit to going hightech myself, Jarrell. I do enough hand motion lining turnouts on my railroad without also controlling the reversing loop that I have. So, I sprang for the price of the newest version of the device at Tony’s, the PSX-AR. I wouldn’t think of describing this fine device as cheap, not for the price and not for the function. It is essentially a mount someplace back and under where it won’t get a knee or elbow into it, and then wire it with four wire ends, two for incoming signal power from your bus, and two outputs to your gapped reversing section. When you power up your layout, it gets powered too. Then you just play trains and let it do the sentinel thing. Silently. Reliably.
If you use Tony’s comtroller or another brand, its a VERY good idea to protect it in some way from physical damage. I formed a pc. of 1/16 alum. sheet into an angle ( about 4x4 )& secured it with screws to shield the unit. Don’t know how many times I’ve hit my head on it…but better than destroying the unit. Jerry
I’ve used an MRC auto reverser for several years with a problem. Installation was amazingly simple. I’ve used a single reverser to control the loops at both ends of my mainline. This works as long as I don’t have an engine running in both loops at the same time. Since I am a lone wolf operator, this works fine. If that was an issue, I would just get a second reverser for the other loop. As I recall, the MRC was relatively inexpensive.
I have a Digitrax Super Chief on my layout, and have three AR1 reversing units, which are easily wired. You only need to isolate a section as long as your longest locomotive consist.
You can also look at Jim Barta and my article in December 2006 Model Railroader.This discribes how to make an AUTOMATIC reversing loop for DCC.
This article was also reprinted in the August 16, 2007 Model Railroad Newsletter that many people receive in their inbox every few days, or even more frequently.
HI
I make a fully automatic DCC reverse loop controller. The system consists of an auto polarity controller and an automatic turnout controller. This system allows a train to enter the loop, continue all the way round the loop and then continue on out of the loop now travelling in the opposite direction. All this happens automatically and completely hands off by the operator. If anybody wants more information then email me at jeffmon@optusnet.com.au.