How to build a 4.5v Gordon

... pulling his express coaches (or what I believe are, some clarification would be appreciated)...

Those blue and white coaches are supposed to be narrow-gauge coaches, they came with Skarloey. more here:

http://ttte.wikia.com/wiki/Agnes,_Ruth,_...d_Beatrice

Gordon's express coaches look like this:

http://thomastrackmaster.wikia.com/wiki/...ress_Coach
also available in red & cream, and blue & cream.