First, I have no exact idea and I doubt any of us will ever know. But I will give you an example.
Perhaps they were working on a tilting track section and wanted it to go through the tilting motions without the train in place. So, they pulled a trick (which I will not describe) to make the master systems computer think the train was on and locked in place. What might happen with a train further down the track from there I have no idea. But it was something like that to save waiting for a train come through and tilt the track.