I stated volunteering there in 1992 when it was at its original 12 acre location. In 2002 I moved to NC long after the museum had moved to a new location on the opposite side of the NS main line a mile or so north to a former privately owned railcar maintenance facility. I continue to volunteer periodically when I have a chance and some free time on visits to my 6 y/o grandson and his parents (who don't count when you have a train-nut 6 y/o grandson).
It is virtually all volunteer run. As far as I know, the only paid people were the front gate admission people but that may have changed (to them not being paid).
Wonderful museum with a great management team unlike years past. They are open about letting you walk though historic cars. If I were there when you came, I'd take you through the shop area.