Bachman Reverse Loop Module

[Sheperd1]

Can module be used with AC current  such as with S-gauge trains?

[Jim Banner]

The modules are designed to work with ac trains which determine their direction on board and not by track polarity, but only if the current is within the maximum rating of the module.  Trains running on DCC are powered by boosters with typically a 5 amp maximum output.  This maximum is controlled by an electronic circuit which instantaneously shuts down the power if the current tries to exceed the rated output.   S-gauge trains are traditionally powered by transformers rated up to about 6 amps (90 watts at 15 volts.)  This maximum is controlled by a thermal circuit breaker which shuts down eventually when the current exceeds the rated output.  Unfortunately, the short circuit current can exceed the rated current many times over while the circuit breaker heats up and eventually trips.  In my opinion, the Bachmann reverse loop module would work with conventionally powered S-gauge trains but only for a short time.

If you were to use an electronically limited power source that it could not exceed about 5 amps, then you might be successful.

Depending on the nature of the reverse loop, there are other ways of reversing the power automatically.  For example, if it is a simple loop (one way in, one way out) then a set of contacts linked to the turnout controlling the loop will do the job.  The contacts could be in a switch machine or in a latching relay (e.g. Atlas Snap Relay) that throws along with a switch motor or even a relay operated by a switch position monitor (micro switch, optical device or magnet and reed switch.)  This article gives more details:
http://members.shaw.ca/sask.rail/dcc/loop/loop.html

Jim