I have posted this before but is worth repeating. For reverting and stopping many resort to a DPDTCO switch. Whilst this works if you are in a rush to stop the train and hit the switch it is so very easy to go from forwards to reverse, a real problem if the train is flat out and a potential motor and gear train damaging possibility. This solution shown below is a safer bet using 2 x SPCO switches one each side of the Loco for access. Note that you must wire things this way, if you put the feed in the centre opposing switch locations will cause a short.
both switches forwards or reverced make the train go, one opposing and the train stops. So much easier to just flick one switch if you have that Emergancy.