Brookfield's seven-million square foot Manhattan West development is ideally positioned at the gateway of Manhattan's newest and most vibrant neighborhood, the Hudson Yards District on the west side of Midtown. Manhattan West includes four new high-rise towers and the major renovation of an existing building. The development is constructed over the rail corridor serving New York’s Pennsylvania Station, the busiest rail corridor in the United States. MRCE designed an innovative foundation system consisting of rock socketed caissons and spread footings, with tie-downs to support and anchor the bridge-like platform over the rail corridor. The platform was constructed in a single column-free span using unique precast concrete solutions and launching gantry systems. To keep an eye on adjacent structures during construction, MRCE designed and implemented a comprehensive monitoring program. MRCE monitored structural performance of the long span box girders over the rail corridor.