 Despite the warning track's presence, it is common to see outfielders crash into the wall to make a catch, due to a desire to field the play regardless of the outcome, because they fail to register the warning in time, as they are looking up at the fly ball, or because they don't know how many steps they'll have on the track.The "track" part of the term comes from Old Yankee Stadium, where an actual running track was built for the use of track and field events.In 1949 Major League Baseball formally began requiring a warning track.