The most straightforward and legal way to do this is through one of the NARCOA affiliated runs. Also, be aware that it is easier to end up with a NARCOA and FRA compliant speeder if you start out with a speeder built by one of the recognized manufacturers, as opposed to starting from scratch. There are still fairly cheap rebuildable cars out there. Check out www.narcoa.org for more information. And the next NG motorcar run will be Aug 20-22nd on the C&TS and the 24-26th on the D&S, so come watch!
Philip Walters
D&RGW 4054
1985 Fairmont MT-14L3