Skidmore, Owings & Merrill LLP (SOM) is an American architectural, urban planning and engineering firm. It was founded in 1936 by Louis Skidmore and Nathaniel Owings in Chicago. In 1939, they were joined by engineer John Merrill. The firm opened its second office, in New York City, in 1937 and has since expanded, with additional offices in San Francisco, Los Angeles, Washington, D.C., London, Melbourne, Hong Kong, Shanghai, Seattle, and Dubai.

Moynihan Train Hall is an expansion of Pennsylvania Station, the main intercity and commuter rail station in New York City, into the city's former main post office building, the James A. Farley Building. Located between Eighth Avenue, Ninth Avenue, 31st Street, and 33rd Street in Midtown Manhattan, the annex provides new access to most of Penn Station's platforms for Amtrak and Long Island Rail Road passengers, serving 17 of the station's 21 tracks. The hall is named after Daniel Patrick Moynihan, the U.S. senator who had originally championed the plan. The building's Beaux-Arts exterior resembles that of the original Penn Station; both buildings were designed by the architectural firm of McKim, Mead & White.