Does Power Functions 88002 fit a gray-era train and run on gray-era tracks? Is the Power Functions Train Motor (set 88002) the right height for a gray-era train (set 7745)? Does the Power Functions Train Motor run OK on gray-era tracks?
As seen in this video, it is possible to add Power Functions to set 7745 and run the train on gray tracks

Lego Train 7745 with Power Functions


photo from Brickshelf gallery

Another video
Lego 7745 powerfunktion