Auto-reverser options : LUSENET : Wiring for DCC : One Thread


My club is building a modular set up that will have two reverse loops - one at each end. We were planning on using Loy's Toys ARSC, but I just found out it will only work with locomotives that have all wheel pick up. The members of my club run equipment that does not have all wheel pickup, and they are not inclined to install wipers. So I need another solution.

I was looking at Tony's Train Exchange PS reverse/breaker unit. Can anyone tell me about this unit? Does it require a reverse section longer than the longest train? Is all wheel pick up required?

Thank you for your replies.

John Gibson Rocklin, CA

-- John Gibson (, January 16, 2003


If you have a single mainline track with a true reverse loop at each end, it must be longer than the train or you will crash into your own rear-end. Think about it. [o_o]

The Loy's Toys ARSC is unique in how it works. It does rely on detecting locos (Vs other cars) by seeing both rails of a short isolated track section or 'portal' becoming energized when an axle with both wheels energized by connections to other pick-up wheels on the loco rolls in. This essentially requires that both wheels on the same axle must be connected as electrical pick-ups and be connected to other axles on the either direction of travel. Modern diesel locs have all wheel pick-up...No problem. Older steam locos and even some late models do not do this, and they may have one-sided pick-up on tender trucks. They will need to be modified, or the ARSC scheme may not work. [It will also get fooled by a passenger car with all-wheel pick-up.]

All other auto-reversers depend on detecting a (temporary) short circuit on one or both rails as a pick-up wheel crosses a rail gap. Tony's PS-Reverser, Lenz and MRC work that way. The reversing track loop/section must be longer than the entire train, or at least that section with steel wheels, to avoid simultaneous bridging of the electrical gaps at both ends.

-- Don Vollrath (, January 17, 2003.

Part 2 There are other options... 1. If you have a simple loop at each end - Use a relay in conjunction with the track switch to set track polarity to agree with the selected train path. A relay is necessary to avoid any significant power interruption as the turn-out changes state. 2. If you have a short reversing track section - Use a conventional auto-reverser, but extend the electrical reversing block to be longer than the train by using relays to re-select the source of track power and polarity of the extending sections to be either that of the main or matching the auto-reversing section, again depending on what track switch paths are selected. The shortest reversing track must be longer than your mu'ed loco consists. 3. You can get by with steel wheels on freight cars and a short reversing section if your track gaps provide a small electrically dead spot as the wheels pass....But... 4. Don't use passenger cars (or other trucks) with steel wheels designed for power pick-up. (The wheels on one side of the axle are electrically connected to each other via the metal truck frame even though there may not be any actual pick-up.) Ditto for pusher locos.

-- Don Vollrath (, January 17, 2003.

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