Hi JPV:
Thank you
The N scale kit measures 16 x 6 x 5-1/2" 40 x 15 x 16.2cm
The HO scale kit measures 19-3/4 x 8-1/4 x 7" 49.3 x 20.6 x 17.5cm
Walthers does not make O scale kits any more. They sold their tooling to Atlas O who has been very slow in releasing kits. I tried a quick Google search for an O scale version thinking maybe someone has an old kit but no luck. Walthers has a lot of beautiful HO / N scale structures that I and a lot of other people on this forum wished were produced in O scale.
Joe