Mike R

Hello everyone. I'm new to this wonderful forum and wondered if anyone can help? I have a Hornby Dublo 3 rail Standard tank loco that refuses to start when power is applied! I can get it to run slowly after turning the armature with a cocktail stick. But once I stop it, it needs a other 'prod' to start running again. My other locos are fine so its not the controller or track. Any help would be very much appreciated. Thank you all.