Sounds interesting, but from what I read it won't allow you to cycle directions when set...though this is fine for block wiring and station stops, you won't be able to change direction unless you shut it off...you can do the same thing with your engines by locking them in forward. Either way you go you'll have to do something either to the engine{s} or that device.
Isn't the lowest required voltage supplied to the track that keeps the engine from cycling something like 5v or so...with a sellect throttle adjustment via trail and error one could keep the stopping voltage high enough to keep the engine from cycling...that'd be a task with my ZW....