Product Support for: AutoReversing -> Automatic Reverse Controller-Single (AR1)

The AR1 is usually located close to the point where the gaps are cut for the reversing loop. The length of the reversing loop is determined by the maximum length of the train that will use the loop.1. Turn off track power. (Note: Failure to turn off power before connecting your AR1 may damage your AR1.)2. Connect Track Power from Rail A and Rail B mainline to the AR1. Rail A connects to terminal 5 and Rail B connects to terminal 4.3. Connect the wires from the reversing section to terminals 1 & 2 on the AR1. (Note: terminal 3 ...

How do you wire an AR1 with a BD4 so that you get block detection within the reverse loop and without the BD4 permanently detecting the AR1? It should be wired with the AR1 between the power source and the BD4. All four detection sections of the BD4 will have to be inside the reverse loop.

  One major consideration is that the reverse section controlled by the AR1 must be longer than the longest train. It is a common misconception that the AR1 will work with an analog controlled ("DC") locomotive; it will not. The AR1 is meant to be used only in a DCC enviroment. The AR1 coordinates the phasing of the reversing section with that of the mainline (non-reversing) section of the layout.  Because a Digitrax layout can be a complex enviroment with detection and transponding, etc. consult the approriate Digitrax user manuals and the Digitrax Tech Support Depot knowledge base.  

When using an AR1 with the Zephyr Xtra, we suggest you change Option Switch 18 to Closed (OPSw18='c').  Option Switch 18 extends the DCS51 booster short circuit shutdown time from 1/8 to 1/2 second.  By increasing this Option Switch setting to 1/2 second, this allows the AR1 to change the track polarity before the DCS51 booster reacts to the momentary short caused when the train passes over the reversing section gaps.   To change Option Switch 18, do the following:   Press PROGRAM Press SWITCH Press 1 Press 8 Press c (CV-WR, lower right) Press EXIT   You will still ...

The tuneable trip current (TTC) adjustment allows you to set the current at which the reversing section reverses when the train crosses the gap into the section. This allows you to improve the operation of your reversing sections.The tuneable trip current is adjustable from .25 amps to 8 amps. Turning the TTC screw clockwise increases the current trip point and turning the TTC screw counterclockwise decreases the current trip point. The total adjustment is approximately one half revolution of the TTC adjustment screw. The TTC adjustment is made using a full load on the reversing track--the total number of locomotives/cars ...

  Can the AR1 or PM42 be used to power the track of a turntable? This track section would be electrically isolated from the surrounding tracks which would all be powered from the same booster. Yes. A good number of our customers use either the AR1 or one node of a PM42 to handle turntable powering issues.

  Digitrax AR1 is a DCC Automatic Reversing Controller.  We have become aware of another product of a similar name that may cause our customers some confusion. Circuitron makes an automatic reversing unit called the AR-1 that is used for automatic reversing of analog powered trains. The Digitrax AR1 is not the same device and does not work in the same way.

Q: I want to use the AR1 for a reverse loop between two different power districts (i.e. different booster for each connected track). Is this possible or do I need to make a special wiring set-up to do this? SThis diagram shows how to do this The usual rules apply, the AR1 track section must be longer than the longest train you will run.

Q: I am building a new DCC layout that will include a logging spur that is simply a single long piece of track with no loop. I want to have a train go back and forth on this track which automatically reverses when it gets to each end. While the AR1 was designed for reversing loops, can it be wired to simply reverse a train on a straight piece of track? A:  Not in the way that you intend. One of the interesting problems with DCC is that we often still think in terms of DC, where the track polarity ...

My layout is the Apex & Hypotenuse design, from the Atlas design. I was wondering where would you suggest I wire the AR1. We remember this layout design, if for no other reason than its ingenious complexity. This railroad initially appeared in the Custom Line King Size Plan Book - H0 Railroads You Can Build, originally published by Atlas Tool in 1966. This book was yet another collaboration between the late John Armstrong and illustrator Thaddeus (Tad) Stepek. This railroad must have required a certain level of dexterity by the operator since the reversing segment is actually two different return ...

When using the your PM42 with an AR1 Auto Reversing controller do not use the "fastest setting" in the Short Circuit Sensitivity Settings section:

We have designed a layout at my place with double main line with reverse loop at each end. Plus there is a branch line with two reverse loops that in one loop is connected to the main line. The main lines stay double track even at the split. The branch stays single with only one connection with the main. My plans where to use the AR1 for all my reverse loops and the PM42 for my power control. What if any problems do you see with all these loops? Nothing, if you can guarantee that at any given time only ...

Q: How do I use the AR1 and automatically control the turnout? I'm confused here. It is good that the AR1 controls the switching of the track power for a reverse loop automatically but it seems the turn out direction also needs auto control. Am I missing something here? Need help understanding...Please explain. A: The AR1 is handles correcting the track polarity mismatch when a reversing section is encountered by a locomotive. When the polarity inside the reverse section does not match the polarity outside the reverse section, the AR1 detects the short circuit and flips the polarity so that ...

The Texas & Southwestern has a reversing loop, and DCC insures reliable and simple operation of trains in the reverse loop. This reverse loop is handled with a Digitrax AR1 Auto Reversing Controller. The automated features of the AR-1 make for seamless train movements, but an issue quickly arose. Because a reverse loop in a traditional DC-powered model railroad environment required manual operation, the track insulating gaps for the loop were usually located for the convenience of the operators. So the track gaps of the original track plan were situated to keep this inconvenience to a minimum. Note also all ...

In earlier generations of model railroading, the reverse loop (reversing section) was the bane of many model railroaders. As the rails of a track come back upon themselves, an electrical short circuit is created. In the analog control world, the solution is to use toggle switches and special wiring to allow the locomotive to move on to the next block. Electromechanical solutions relying on relays and track detectors can also be used to automate reversing on an analog layout. The wye is another example of a reversing section on a layout. One of the advantages of digital command control is ...

I have multiple reversing districts, do I have to buy a separate booster for each one?You can run more than one reversing district off a single booster, but there is the potential problem that might arise is if you have more than one set of wheels crossing more than one set of gaps at the same time. In this case, the booster will detect a short and shut down (unless the polarities just happen to be matched up in which case you won't see a problem). We recommend that you use the AR1 Auto-Reversing unit or the auto-reversing capability of the ...

Digitrax auto-reversing units such as the PM42 or AR1 require a "hard" short for them to work properly, which means there must be good current flow to both sides of the gaps, on the reversing section side and on the "normal" side.  For this reason it is poor practice to put the gaps immediately behind a turnout relying on the points of the turnout to supply the current to the "normal" side of the gaps leading to the reversing section.  Resistance through those points often reduces the current to where a good short cannot occur preventing the auto-reversing unit from ...

Connecting a turntable to a DCC model railroad is easy.  Each of the tracks approaching the rotating turntable bridge should be wired with the same orientation.  The power feeds through a pair of conductive rings to a pair of electrically conductive brushes that are wired to the rails of the turntable bridge.  DCC power is fed to the turntable bridge through an AR1 Autoreverser; when a locomotive enters or leaves the turntable bridge, the AR1 properly orients the DCC signal.  Some turntable designs have a "split-ring" electrical pickup, where the two electrical contacts that power the two rails on the ...

I am building a layout that will have two completely separated track plans; not connected with each other by any track. I am running one layout with a Super Chief that has one AR1 reversing controller.  I would like to run the second layout with the same throttle. It will have a reversing loop, as well as a turntable.  I have thought that I could run the second layout with a booster and a couple of AR1s or PM42.My questions is, will I have any problems with the reversing loops, especially if one on each layout is triggered at nearly ...

As originally conceived, the Texas & Southwestern was set up with a very simple DCC system. The railroad uses a DCS50 Zephyr as its command station and booster. The Zephyr is connected to a central power bus, and all tracks, stationary turnout decoders and the automated reverse loop unit are connected to it. Likewise, the LocoNet connections are a series of simple cable connections starting at the Zephyr and ending at the last Universal Panel. The T&SW works well with this arrangement, but there are additional devices that will enhance the operation of this railroad. Digitrax PM42 Power Management System ...

This Atlas Snap-Track layout appears in the Atlas Model Railroad Company's book "Beginner's Guide to HO Model Railroading". It includes a reversing section which can be controlled with a Digitrax AR1. DC Control For DC operation, Atlas specified an Atlas Controller (for the reverse loop), two Atlas Selectors (to control eight track segments) and seven controllers for the railroad's turnouts. DCC Makes Things Simple With DCC, the wiring of this railroad is considerably simpler. Because each locomotive has a unique address, the section insulated gaps and the two Selectors are not necessary. Likewise, the Controller is replaced with the AR1 ...

Good DCC practice means good planning for the electrical needs of the railroad. Here, we talk about the power needs of the Texas & Southwestern. Anticipating Power Consumption The core of the Texas & Southwestern's DCC control system will be the DCS50 Zephyr, which is very appropriate for a small railroad. Zephyr has 10 "slots", memory locations in the command station each holding an active decoder address. Rated at 2.5 Amps, the Zephyr should also be enough to handle the power needs of the railroad, but if more power is needed, then T&SW can easily be expanded with an additional booster ...

DCC Automatic Reversing SectionsVirtually all automatic reversing will fall into 3 categories with the wiring principles for all being the same:1. Reverse Loops2. Wyes3. TurntablesDCC has the ability to automatically reverse sections of track we call Reversing Sections while our trains are running and not affect the direction or speed of the trains. This is because we put a constant square wave AC current on the track and control the trains (locos) by sending messages to them (actually to receivers we call decoders) to tell them what to do such as start, stop, change directions, etc. . We are thus ...

At first glance, the typical switching railroad would not seem to be a good candidate for DCC operations. Yes, there may be only one locomotive on many of these railroads, but that locomotive can still benefit from DCC. By adjusting the starting, mid-range and maximum speed values of this locomotive, you get very good slow speed control, perfect for the switching railroad. And, of course, if you add a second locomotive, then DCC becomes the clear choice because you are not longer having to throw toggle switches just to move around the yard. The DCC environment also gives you turnout ...

Since many Zephyr and Zephyr Xtra Starter Sets are used on smaller railroads, a natural choice for setting up an automatic reversing section would be an AR1. If you have more than one reverse loop, then the PM42 is a better choice. These automatic reversing strategies will work equally well for any Digitrax system using any Digitrax Starter Set.  Alternately for larger railroads, an auto reversing booster such as the DB150 can be used for automatic reversing if the section is large.

This section discusses the installation of the physical wiring of the Texas & Southwestern. Underneath the completed Texas & Southwestern are various wires and cables which allow you to operate your railroad. Initially, seeing all these wires can be intimidating, but as you will note, they have been grouped and bundled so that identifying the individual wires is easy. There are two groups of wires under the railroad; one group, the power bus, delivers power to the tracks and to the stationary decoders that operate the track switches. The other group of wires is the black cable for LocoNet and ...

Q:  What is the preferred way of protecting a reverse loop with circuit breaker management and still having automatic reversing? A:  There are two ways of protecting a reversing section with a circuit breaker and reversing section controller. 1.  Use one PM42 (circuit breaker manager) and one AR1 (automatic reversing section controller). 2.  Use two PM42s (one as a circuit breaker manager and one as a reverse section control). The following diagram displays both methods: a) The first method (left), is where one section of a PM42 configured for circuit breaker operation feeds one or more AR1s (automatic reversing section controller), or b) The second method ...

Q:  How do I wire a double crossover? Each crossover results in a reversing loop. Should I use a PM42 or AR1? This is O scale (2 rail) if that would have any bearing on your answer. A:  Without a drawing to see how things are laid out, this can only be a guess, but a couple rules do apply. The reversing sections must be longer than the longest train. And there should be only one train in the reversing section at a time. It also seems to be a good idea to keep the reversing sections away from the ...

Q:  Can two sections of a single PM42 be configured to perform both the task of a circuit breaker and also automatic reverse section control for a single reverse loop? The PM42 can be configured so that one section of the PM42 is used for circuit breaker operation, feeding into another section of the same PM42 which is configured for automatic reverse section control. In the field, this configuration has been found to be unreliable in some layout configurations.  If you are having problems getting this to work in your setting, we recommend using an AR1 to handle the automatic reversing secion.  The ...

In response to a request, here is a semi-official track plan of the Texas & Southwestern: The railroad uses Kato Unitrack: 249mm radius curves 282mm radius curves Seven #4 Right turnouts, configured to be "non current routing" Five #4 Left turnouts, configured to be "non current routing" Two 90° crossings A variety of straight tracks, including the 20-091 Short Track Assortment Three 20-050 Adjustment Tracks Several 24-818 Terminal joiners to supply power to the railroad and to connect the AR1 to the reversing segment Insulated Unijoiners were used to define the reversing segment. Alert readers will note that the tracks ...

Case Study - Texas & Southwestern The Texas & Southwestern is a small N-Scale model railroad that features a Zephyr. Here are a variety of short articles which detail the various facets of the construction and operation of this railroad. Background-Part 2 The idea behind the railroad. The Railroad-Part 3 Planning the railroad Track Plan- Part 4 Powering the Railroad-Part 5 Zephyr makes things easy. Wiring the Railroad-Part 6 Hooking things up for reliable operation. Reverse Loop-Part 7 AR1 makes things easy, but a little change in thinking is sometimes necessary. Programming Track- Part 8 A convenient feature. Zephyr Heat Problem- ...

Problems occurring on most auto reversing sections are a result of improper wiring or gapping. Digitrax auto reversing units such as the PM42 or AR1 require a "hard" short which means there must be good current flow to both sides of the gaps, on the reversing section side and on the "normal" side. Our experience has been that over 90% of reversing section problems are a result of improper wiring or improper gaps. Another 5% is a result of improperly wired or configured auto reversing units. It is poor practice to put the gaps immediately behind a switch (turnout in ...

  I have an "old" vintage mid 1970's Atlas Turntable and I need to know how to wire the bridge track using DCC. Does it need an autoreversing unit or not?No. The Atlas H0 turntable is an evergreen for the model railroad hobby. It was easy to install and simple to wire, making it quite popular.Power is fed to the turntable bridge by connecting the track power feeds (black and red) individually to two screw terminals; these terminals are built into the portion of the Atlas turntable base which also includes the turntable manual crank handle. The turntable itself is ...

What is it and how do I find a DPDT?It's an electrical switch; double pole - double throw (DPDT). Here is a schematic of a DPDT: More typically, they look like this: The DPDT is very common to model railroading and found at just about any store that sells electronics.  It comes in a variety of arrangements, with the most common being a DPDT Center-Off switch.  Analog OperationsIn the early days of Direct Current model railroading, reverse loops had to be controlled by hand, and the DPDT was perfect for the job.  The DPDT was wired in such a way ...

Q:  I am not sure where to begin. Dabbled in O & HO over the years and am now starting into S but have no knowledge in DCC. My layout is drawn, Dog Bone, with an over size of approx 20' by 11'. As of now there will be 8 turnouts and perhaps a turn table will be added or more turnouts. My intent is to run maybe 3 or 4 engines max. My only purchase so far is a Showcase Western Maryland, scale, which includes DCC with sound. My next comment is HELP! I do have a 2006 Summer ...

Power Management is a concern on every layout.  With Digital Command Control, the main concern is that enough power is supplied to evey track section on the layout so that the digital signal is transmitted to the decoders in the locomotives and turnouts.Each locomotive uses power from the track, some for the motor, some for headlights and other functions and some for the command control electronics in each locomotive.  More electrical power is necessary to run more locomotives on the layout.  Digitrax boosters provide between 2.5 amps & 8.0 amps.  A small N Scale or HO Scale layout with two to ...

  This document outlines the power requirements for Digitrax LocoNet accessories.  To simplify wiring, Digitrax recommends providing individual power supplies for like accessories.  For example a power supply or power buss which only powers the PM42s.  A power supply or power buss used solely to power multiple DS64s.  UR9x and UP5 panels can be daisy chained provided adequate current is provided to properly power all the panels.  Through the use of individual power supplies, the chance of Ground Loops or sneak paths back to ground is minimized.  Using individual power supplies will also make troubleshooting much easier.  Many Digitrax LocoNet ...

The slip switch is a track element that has both a crossing at grade and also a set of movable points which allow trains to both cross another track and also change track.  The Crossing The crossing allows tracks to cross each other at grade.  The Slip SwitchThe more complex slip switch allows trains to both cross and to change tracks: In the schematic below, you will note that the slip switch is more compact than ordinary turnouts.  As a result, they are often found in high track density areas such as passenger terminals, where space is at a premium. ...

I have a 4x8 H0 scale layout.  I'm 13 years old and REALLY thinking about switching to DCC, I need to know really fast because I want to ask my parents to get it for Christmas.You wouldn't know by looking at those who edit the Tech Support Depot, but there actually was a time when we too were thirteen, and just starting out in model railroading.  In many ways, we still are thirteen years old; we just can't move as fast.  Consider this photograph from our youth: This little bit of ancient model railroad history dates back to the 1950's, ...

This H0-scale railroad track plan first appeared in the Atlas Model Railroad Company's book "Six Railroads You Can Build", written by John Armstrong and illustrated by Tad Stepek. This book was first published in 1958 and has been reprinted several times. A classic bowl of spaghetti, the Transbay Interwoven has two reversing loops and a turntable. DC Control For DC operation, Atlas specified three Atlas Controllers (for the reverse loops and the turntable), two Atlas Selectors (to control eight track segments) and ten controllers for the railroad's turnouts. DCC Makes Things Simple With DCC, the wiring of this railroad is ...

Digital Command Control (DCC) has specific electrical requirements that must be provided for your layout control system to operate properly.Input PowerAll DCC systems require an external power supply.  Digitrax manufactures several power supplies for our command stations and boosters: The 3 Amp PS415 (the Zephyr Xtra power supply) The 5 Amp PS515 for all Digitrax 5 amp command stations and boosters The powerful 20 Amp PS2012 can be used for multiple 5 and 8 amp command stations and boosters  Additionally, the PS14 is available to power various other devices for your railroad.  Digitrax strongly encourages you to use our power supplies to insure satisfactory ...

Digitrax Complete Train Control By Zana & A.J. Ireland Digitrax Complete Train Control makes reliable, realistic train operation and simplified layout wiring a reality. Digital Command Control is incorporated within the Digitrax system to let you control multiple trains independently on the same section of track without blocking. In the real world, engineers control the speed and direction of real trains. Engines operate under their own power independent of the track. Each engine has its own motion characteristics like how fast it speeds up (acceleration) and how long it takes to slow down (deceleration). A locomotive's performance is influenced by ...