It will not leave reset unless track power is below 10 volts. Make sure track voltage is below 10 volts and it should go. I have a couple PS-1 equipped locomotives that can be really picky about that. If I hit direction and they reenter reset, I lower the track voltage and try again, and keep doing so until they move.
If you still can't get it moving, it is from the correct era of locomotives that can enter deselect mode (See option two on this page.). My '96 NYC Hudson did this. If that is the case, you need to order a new chip from MTH, which they still sell.