In 1945 Mayor Robert S. Maestri appointed a Railroad Terminal Board and charged it with negotiating with the railroad companies operating in New Orleans to assure construction of a new passenger terminal and elimination of the numerous hazardous grade crossings located throughout the municipality. On October 22, 1947 the City and the railroads signed an agreement to build a new Union Passenger Terminal. It called for the railroads to pay for the construction and maintenance of the Terminal on property owned by the City, with ownership of the building also falling to the City. The agreement also created the Union Passenger Terminal Committee and gave it responsibility for building, and later operating, the new facility. Representatives of the City, the Railroad Terminal Board, the Public Belt Railroad Commission, and the eight private railroad companies served on the Committee. The agreement required that the entire cost of maintaining and operating the Terminal be borne by the railroads and that the chief accounting officers of the railroads, or their designees, would constitute the UPT auditing committee. The UPT Committee appointed a terminal manager to supervise all operations of the Terminal, including the hiring, disciplining, and firing of employees. Other duties and responsibilities of the Committee included negotiation of labor agreements with the various classes of employee, maintainence of insurance on all Terminal properties, and the purchase of switching locomotives.

In 1969 the NOUPT Committee leased space in the terminal building and on other terminal property to Southern Greyhound Lines for the operation of interstate bus service in and out of New Orleans. Over the years the NOUPT Committee also leased portions of the terminal property to the New Orlean Aviation Board (for operation of a heliport), to APCOA, Inc. (for parking lots), to the Falstaff Brewing Corp, to Louisiana Industries, and to the U.S. Postal Service.

In 1970 the federal government established the National Railroad Passenger Corporation (Amtrak). That new railroad passenger service operated at the NOUPT under trackage contracts with the original railroads until 1974, when the City entered into an agreement with Amtrak for use of the terminal facilities in its own right. In 1976 Amtrak and the City, through the NOUPT Committee entered into a new agreement whereby all responsibility for passenger services at the terminal, including ticket sales, passenger information, boarding and deboarding control, baggage handling and redcap services was transfered to Amtrak. Finally, in the following year the parties agreed to Amtrak's assumption of all maintenance and operational services at the terminal.

On May 3, 2002, after lengthy negotiations, the City took over full operation of the terminal, paving the way for renovation of the building and redevelopment of portions of the NOUPT property. The New Orleans Building Corporation will manage the terminal and oversee new projects such as the construction of a new parking garage, creation of a "nerve center" to control railroad and traffic signals throughout the city, and other new endeavors, possibly including warehouses for city agency use and a hotel development.