Yes, Sperry is planning to drop the doodlebugs in favor for the trucks. They do more thorough testing of the rails than the 800 series trucks to, but their new 900 series trucks that they are coming out with now do the same type of testing as the 100 series railcars. Another determining factor is the availablilty, railcars can't move around as fast, must tie up after some time on remote spurs, hy-railer trucks can pull in at the nearest motel off the interstate. I have seen both vehicles, while one is more historical, I would much rather work on a hy-rail truck.
1.) Communication between chief technician and driver is easier.
2.) You can operate them with fewer people.
3.) Yes, you can get them off the rails at the nearest crossing, allowing that pesky coal train to roll by during your test.
4.) I would much rather sleep at the Drury Inn than a bunk on some musty smelling old 80 year old car.
To answer a couple more questions, they are indeed original doodlebugs, some of the original paint can STILL be seen on the wood framing that is now covered up with the metal yellow skin. They are very historical pieces, but if you see one now, get your photos while you can, they're slowly being replaced for good.
