The scope of the project within Queens also included the construction of two bypass tunnels for Amtrak trains within Harold Interlocking. While eastbound Amtrak trains to New England would be able to go through the interlocking without crossing the paths of East Side Access trains, westbound Amtrak trains to Penn Station would use tracks that intersected East Side Access tracks. East Side Access trains to Grand Central came from the east and would diverge to the northwest while Amtrak trains to Penn Station came from the north and would continue west, so the final environmental impact statement called for a bypass for westbound trains. Around $295 million was allocated for the bypass in 2011, and work on this project started in 2013. However, by October 2015, the tunnels were behind schedule because Amtrak and the MTA could not cooperate on track access schedules. These delays ultimately raised construction costs by almost $1 billion as of April 2018, and in a report that month, the MTA attributed the delays to a lack of cooperation on Amtrak's part. The work at Harold Interlocking also included the installation of a microprocessor-based signal system, replacing the old track circuit-based signal system.