Just another thought on your dilemma. The large railroads that serve thousands of miles of track over several or many states (Class 1), sell off their old Locos and rolling stock and they are often bought by leasing companies or by short lines (MRL when it first started in '86-7 did this) and at first before they decide on a paint scheme (or never) apply a rectangular patch or patches where the new road's business name, reporting mark*, Loco's road number can be painted onto. (* reporting mark. If you are intending to have a reasonably American based RR'd, then an official reporting mark is required e.g. MRL for Montana Rail Link. These are displayed usually on both sides of the long hood, along with a larger version of the number, the sides of the cab, one above the other and on each end. In your case if you use this suggestion it will just be for fun, just something to add interest, but also, if you decide to use DCC as a control system, the number will become it's DCC address. Here I would advise choosing at least a triple digit number at least. You can have a single digit on the loco, but use a multi, such as 004 in your system. Avoid 3, as it is the default factory reset number for all DCC decoders.