Engine polarity

[rbturner]

wfletcher; you are getting good advice here. It also sounds like you have two problems. One is a loco that has been mis-wired and the other in a polarity problem at a turnout.

Like Trainman said with the right rail positive and the left rail negative the loco should move forward. If it does not then you need to flip the two wires feeding the motor. If that is not possible you can also turn the magnet 180°; depending on the type of motor you have.

Maybe try fixing your problems one at a time?