The partition of Ireland in 1922 turned the boundary with County Donegal into an international frontier. This changed trade patterns to the railways' detriment and placed border posts on the Joint Committee's FV and S&L lines and on the GNR line to Derry. Stops for customs inspections greatly delayed trains and disrupted timekeeping. Over the next few years customs agreements between the two states enabled GNR trains between Strabane and Derry to pass through the Free State without inspection unless they were scheduled to serve local stations on the west bank of the Foyle, and for goods on all railways to be carried between different parts of the Free State to pass through Northern Ireland under customs bond. The Joint Committee's Strabane-Derry line was closed in 1954, followed by the remainder of the narrow gauge system in 1960. In 1958 the Ulster Transport Authority took over the remaining GNR lines on the Northern Ireland side of the border. In accordance with The Benson Report submitted to the Northern Ireland Government in 1963, the UTA closed the former GNR line through Strabane to Derry in 1965.