With the talk about digital flow modelling (i.e. openfoam), I've just been toying with simple ideas for scanning vehicles into the computer (on the cheap of course), looks like these folks actually put something together. Just need a hand held line laser, web cam, and a backdrop. Wonder if it could work on a metro (certainly the concept could be applied to a metro)?
FYI, only the low-res version is free, probably something similar in open source land too.
DAVID 3D Scanner