Llangollen Canal part of the London Midland and Scottish Railway soon afterwards. After the takeover by the London Midland and Scottish Railway, regular maintenance was often not carried out, and gradually the canals silted up, so that boats could not operate with full loads. Traffic declined, and was significantly affected by a breach that occurred at the Perry Aqueduct, about to the south of Frankton locks, which effectively closed the Montgomeryshire Canal to all traffic. Traffic beyond Frankton to Llangollen had ceased in 1937, and the Frankton to Hurleston section was not used after 1939. The London Midland and Scottish Railway obtained
Llangollen water from the River Dee at Llantysilio (at the weir called "Horseshoe Falls"). After company mergers, the canal became part of the Shropshire Union System. Until recently it was properly called the Llangollen Branch of the Shropshire Union Canal, though it is now known as the Llangollen Canal. The canal supplied enough Dee water to supply Crewe and Nantwich, and when commercial traffic failed in the 1940s, it was its function as a water supply which kept it open. The canal is unusual amongst Britain's artificial waterways in having a strong flow (up to 2 miles per hour). Since the