Owner and superintendant of the N scale Texas Colorado & Western Railway, a protolanced representaion of the BNSF from Fort Worth, TX through Wichita Falls TX and into Colorado.
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Use a Digitrax AR1.
It is a low-cost solution that has an adjustable trip point which can be set by simply adjusting a pot with a small screwdriver.
Reversing modules work by sensing a short between the two different track sections. If you have a 5 Amp system, almost anyone's auto reverser module will work. I prefer electronic types vs relay types.
If you have a low power beginner system like the NCE Power Cab or Digitrax Zepher, both of which do not put out 5 amps but have considerably less power, there are only a couple auto reverses that will work with them. The PSX AR being one of them, but needs to be programmed for the lower current.
So, read your manual and find out what the current output is, then choose one that works. The MRC auto reverser module should work since you have an MRC system, and the PSX AR will work.
I don't use the PSX series of circuit breakers or reversing modules because they cost more than others that I can use that do the same job, but the PSX ones are top of the line.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.