The Engine Arm or Birmingham Feeder Arm near Smethwick, West Midlands, England, is a short canal which was originally part of a feeder tunnel for a pumping engine. When the Smethwick flight of locks were reduced from six to three, the pumping engine was moved to a new site, which allowed part of the feeder tunnel to be opened up and made navigable, so that coal supplies for the engine could be delivered by barge. The Engine Arm also supplied the pumped water to the 473-foot (144 m) Wolverhampton level of the lowered summit. The arm was extended between 1825 and 1830 by Thomas Telford to carry water from Rotton Park Reservoir to the Old Main Line of the BCN Main Line Canal, and the Engine Arm Aqueduct was inserted to carry it over the new main line constructed at that time, which was 20 feet (6.1 m) lower. The arm is now managed by the Canal and River Trust and the basin beyond the site of the pumping station, which was replaced by a new engine house near Brasshouse Lane bridge in 1892, is used for residential moorings.

The BCN Main Line, or Birmingham Canal Navigations Main Line is the evolving route of the Birmingham Canal between Birmingham and Wolverhampton in England.