ACY - Thank you for your prompt reply. Code 70 is probably more practical, and should look realistic enough for all but the best-calibrated eyes.

Micro-Engineering makes code 40 HOn3 flex track, as well as a track gauge and rail for laying your own HO standard gauge code 55 track. My wishful thinking must have filled in the blank with an imaginary code 55 flex track.

Will the new retooled American 4-4-0 operate on code 55 flex track? I assume that would be the appropriate size for a prototype of this vintage.

It is good to see a new model of a nineteenth century locomotive. particularly with DCC and sound installed. This period has been neglected by manufacturers and magazines lately. A generic black model would be most welcome.