The dock was connected to the national rail network via a line which ran between Canning Town and North Woolwich. When the Royal Dock was first built the railway cut along the docks; to correct this a swingbridge over the entrance to the dock was built. This however slowed journey time, and so a new line was built in 1855 to take the route around the north side of the dock to Silvertown, and a station at Custom House opened where it re-connected with the original line. The older southern line was kept to serve local factories, where it was known as the Silvertown Tramway.