In 2008, Metro-North and the Port Authority of New York and New Jersey (PANYNJ) began a joint feasibility study of a possible branch from the line to Stewart International Airport, which the Port Authority had taken over the year before, ending a seven-year privatization experiment. The PANYNJ withdrew from the study after its first phase, having decided that express bus service could meet the same needs much more cheaply. Metro-North is continuing the study on its own. Future improvements for the line include the completion of the cab signaling system and the construction of a yard near Salisbury Mills to relieve pressure on the Suffern yard.