(01 Jun 2016, 9:18 pm)LeeCalder wrote Is it actually a demonstrator though, or just a spare vehicle due to the amount VOR at Washington at the moment?
It just seems a bit coincidental that the StreetLite has arrived during a time in which there is a shortage of vehicles available, that's all.
Yes, it's a demonstrator.
Plenty of vehicles being withdrawn from the fleet at the moment that can help steady the ship at Washington: 4924 and 5170 being prime examples of this!