sentences:  ScotRail replied that they had been using one-man operated trains since the 1980s, and that the Class 334 trains planned for the Airdrie-Bathgate line had not even been delivered with a conductor's door panel.The strikes were ultimately ended by the unions, in part because of disagreements within the RMT about which principal stand to take on one-manned operations.Other sources point to a "strike breaker" clause in ScotRail's contract, which enabled ScotRail to draw compensation from Scottish taxpayers during a strike, as another factor in the union's ending of the strikes.