 A significant bottleneck in the early years of operations was at Gas Works tunnel underneath the Regent's Canal immediately to the north of the station, which was built with a single up and a single down track.Commercial traffic was further impeded by having to cross over on-level running lines to reach the goods yard.Grade separation of goods traffic was achieved by constructing the skew bridge that opened in August 1877, and the second and third Gas Works tunnels opened in 1878 and 1892 respectively.