The design, construction, operation, and maintenance of the system is part of a public–private partnership. In 1996, New Jersey Transit awarded a "DBOM" (design/build/operate/maintain) contract to the 21st Century Rail Corporation, a subsidiary of Washington Group International, an engineering and construction consulting firm later acquired by URS, then AECOM. Under the contract, 21st Century Rail would deliver a fleet of vehicles, a guaranteed completion date, and 15 years of operation and maintenance of the system, for a fixed price. The agreement was later extended to a 20-year period.