 During Red Sox games and other major events at Fenway Park, extra trains are stored on the pocket track to provide extra service from Kenmore to Park Street to handle exiting crowds.An experimental four-car post-game train operated on April 9, 2011 used the track as a staging point.The pocket track is also used to short turn westbound service from the central subway, such as when the B branch is not operating due to maintenance, accidents, or weather conditions.