From Graces Guide
The Lapal Tunnel (old spelling Lappal Tunnel) is a disused 3,795 yard long canal tunnel on the five mile dry section of the Dudley No. 2 Canal in the West Midlands.
The narrow brick-lined tunnel, built in 1798 by Underhill, had no towpath. It had a very fine bore - at 7 feet 9 inches, just wider than the boats which used it, with headroom of only 6 feet.
Boats originally took about three hours to complete the passage by legging or poling, so in 1841 a steam engine was built at the Halesowen end which drove a scoop wheel to load the tunnel with water. Stop gates could be opened at either end to assist boats along the tunnel in either direction.
The tunnel suffered many collapses and after a collapse in 1917 due to mining subsidence was abandoned. It runs under Lapal, the M5 motorway near junction 3 and Woodgate Valley Country Park. The canal either side of the tunnel is also disused and has been filled in as the tunnel was considered uneconomic to repair.
The Lapal Canal Trust was concerned with restoring the lost canal to make it navigable up to the tunnel from both Halesowen and Selly Oak, and had a longer term aim of restoring the tunnel.
In May 2007 the trust received recommendations from professional consultants, Atkins, that the tunnel should not be restored but replaced by a new up-and-over alignment instead.
Sources of Information
-  Wikipedia