Birkenhead Dock Branch is a disused railway line running from the South junction of Rock Ferry, to the site of the former Bidston Dock on the Wirral Peninsula, England. The branch is approximately 4.5 miles (7.2 km) in length. Although called a branch, the line was accessible from both ends, from Bidston East junction and from Rock Ferry railway station. The former Mollington Street Rail Depot was branched into the line. A section of the line runs through Haymarket Tunnel and a low-level cutting through the centre of Birkenhead; visible from the road flyovers. The disused Canning Street North signal box and level crossing are also situated on the branch. Level crossings are also located at Duke Street and Wallasey Bridge Road.