The Gower Branch Canal is a short canal that links the old and new Birmingham Main Lines. The half mile long canal branches off the Birmingham New Main Line at Albion Junction.
The canal was built in 1836 and allowed boats coming (or going to) the Netherton Canal to get to the old main line without a long detour. I visited the canal (walking it's entire length didn't take long!) back in 2010, you can see my photos here.