Oh, I almost forgot:
The UP thingie is a track recording car, made by Plasser & Theurer in Austria. I remember that I saw quite a similar looking vehicle in a railyard here in Switzerland.
Here is a pic of the most modern of these cars, the EM120. This on was built for the Long Island RR, and it measures track conditions at speeds up to 75 mph (120 km/h)!
Ron