RE: not knowing what this is

that makes sense - so in the case of this and the steamer the tender or carriage is used when the main item can't accomodate an electric motor, it's all clear now thanks to you, much appreciated.

The only other motorize carriage i know of is Mighty Mac.

The trackmaster revolution harvey doesnt need a motorize carriage

Yes the Tomy version of Harvey's coach has a black painted roof. FisherPiece's version is unpainted solid green.
Interestingly though, as an example of how inept FP actually is, they featured the Tomy version of Harvey in their own layout that was pictured on the back of thier insert "collect them all" mercandise checklists!!
That's like using an image of a Big Mac to sell Whoppers!!

[Super]

So did Tomy have 3 versions of this powered coach? Green with black roof, yellow with white roof and yellow with silver roof?

thanks for all the info guys, now i understand what these powered coaches are all about.