I've been asked to do a HOn30 version of a On30 bo-bo Boxcab I did. Problem is I don't model in that scale so I don't know what N gauge chassis are good and easily available. Are there any sites that give chassis dimensions? Alternatively this is a drawing of the loco as proposed , what would fit it? Dimensions in mm, It's being 3-d printed so I can rescale to a certain degree.