As I understand it, the only time workers go into the tunnels while trains are running are to make fixes to problems disrupting the service.
This is done using a train as protection.
I am aware of once a train with 3 emergency responding staff in the cab to fix something, the train stopped in the tunnel. The controller told the staff he wants them done in 90 seconds and to work as fast as they could, it was evening peak. As soon as the train stopped they jumped down onto the tracks rushing dragging equipment out of the cab. Trains still ran in the opposite direction (two track tunnel). In the rush, one of the staff members stumbled getting down out of the train, and fell, landing inches from the power rail- he was very shaken. The power was live throughout....
It is only a matter of time until a serious accident happens when working in this manor!
