Alain,

Thanks for the suggestion... the output circuit was taken from a book and is actually a cloose-loop feedback controller... I just fed the output from the PIC directly to the base of the NPN tranny... but I'll try your suggestions and see if it improves the max speed settings. However in its current state it makes for an excellent branch line controller where slower trains would run...

To give you some idea of the excellent slow speed the PWM gives have a look at this video I've uploaded http://www.micro-heli.co.uk/controller.avi (9mb DIVx format)