Test Results - MRC Auto-Reverser - December 1998 update

Copyright (c)1998, Bruce Helbert, bvl@eskimo.com, used with permission

[MRC product page]

What it is

The MRC Auto-Reverser is a cool little bug. It has four wires, one pair connects to the DCC booster output, the other pair connects to the reverse-section tracks. This could not be simpler. The Auto-Reverser is rated at 2Amps. The MRC Auto- Reverser sells for $24.95.

What it does

Internally, the Auto-Reverser has a relay which reverses the polarity of the output. Functionally, when the Auto-Reverser detects an over correct condition it changes the state of the relay and with it the polarity of the output. This makes the operation of reverse loops transparent to the operator, they require no intervention other than aligning turnouts.

How it worked

The Auto-Reverser was installed on a classic reverse loop on the Teton County Railroad. Previously the reverse loop had been controlled by the second output of a dual-5 Amp NCE Master Series Booster. This is a classic reverse loop, used to turn trains for a local switching point. There is a grade on the loop, so trains going in one direction will draw more current than the other. The track is about 20' long, much longer than any trains which would use it. (This is important, with this or any reversing loop. Trains must not be allowed to cross both gaps at the same time or the DCC booster will shut down the layout.)

The Auto-Reverser worked well up to its 2Amp rated capability. A string of 4 MU'ed Proto2000 GP9's and GP20's ran over, under, around, and thru without any problems.

MRC Auto Reverser Tests [MRC product page]

Tony's first evaluation of MRC's Auto Reverser for DCC is completed and shows good results.

The MRC unit was installed in a large operating layout containing 3 separate reverse loops. This layout currently uses a Digitrax Chief & DB100+ booster for reverse operations.

In all operation modes or conditions, steam/diesel & MU's the DB100+ worked well. We replaced the DB100+ with the MRC unit. The results were impressive, in all cases the MRC Reverser matched the performance of the DB100+. The MRC unit is limited to a 2 Amp current which should work in most applications. The wiring is simple: Rail A&B mainline DCC input & rail A&B reversing DCC output to isolated reverse sections.

Prod # AD520 - MSRP $34.98 - Tony's $24.95

Notes:

(1) More testing will follow in some problem loops.

(2) The MRC unit may obsolete the need for and/or reduce the cost of other mfg's DCC boosters. Not only does the booster and reverse feature add to the cost of DCC boosters, it also reduces the effective starting load as demonstrated by Digitrax's DB100 units not starting when an incandescent load (lights) of about 2 Amps is present. Eliminating the auto reverse from DCC boosters would improve the starting load tolerance and reduce costs.

(3) Thanks to Tony's associate Jim Ferguson of North Troy, VT, and his great "Great Northern" Pike for testing the MRC unit.

The following is from Steve Zeff:

The MRC Autoreversing device worked flawlessly in a wide variety of scenarios we devised:

1) We tested about 15 different locos (mostly diesel) in various configurations. Some were small some were big. Some had low current drain, some were high.

2) Of particular significance were our large MU configurations where we have as many as 6 conducting trucks with 3 locos.

3) Our Mantua Hudson steam loco ran just fine.

4) We tried trains with/without lighted passenger cars.

5) We ran the trains in and out of our reversing loop back and forth, fast and slow.

6) We couldn't make the unit fail.

We previously had another autoreversing unit installed which we were not happy with.

We welcome comments or suggestions from readers; please write or call.