Adding to the reaction time is trying to determine "Is that train on my track or one of the others?" If you look at the photos the train was on the center track of three...and it's on a sharp CURVE. The train ahead is stopped and from the angles involved, it is difficult to determine which track it's really on, especially with the fence in the way. Big hole it for a train on the next track? That took a few seconds to determine, and given reaction time, time for the brakes to apply, etc. the brake application may be appropriate.