Let me add to the chorus about the B&M rules. The link below leads to an ICC accident report in which a Sperry Car operating as a train is wrecked because the flagging rules were not followed:
http://dotlibrary1.specialcollection.ne ... 5C3979.PDF
After that wreck (I don't know if it was a direct result, but eventually they were changed) the rules were changed. As part of the new rules in ABS territory a track car could receive a "Line C". It would say something to the effect of "Operate between Waltham and South Acton. Clear for trains 419, 421 and 423." It was the foreman's responsibility to get out of the way. The trains were not notified you were out there, nor were any blocking devices applied. The dispatcher was not allowed to run extra trains without having noted them on the Line C. It certainly kept you on your toes.
In 1986 when Amtrak was hyrailing the area prior to taking over the Commuter Rail service, we had to hyrail them around. You should have seen some of the looks when we would clear for a train, and hop right back on after the train passed.
Amtrak guy: "Aren't you going to call the dispatcher to get the track?"
Us: "Nah, don't feel like it today."
Those rules were gone very quickly after Amtrak took over.