Smethwick Junction (canal)

Smethwick Junction
Two Horseley Ironworks roving bridges - the further bridge spanning the Old Main Line
Specifications
Status	Open
Navigation authority	British Waterways
History
Date completed	1829

Smethwick Junction (grid reference SP028890) is the name of the canal junctions where the Birmingham Canal Navigations Main Line Canal from Birmingham splits into the BCN Old Main Line and the BCN New Main Line near to Smethwick, West Midlands, England.

The Birmingham Canal was authorised by an Act of Parliament in 1768, and ran from Aldersley Junction, where it joined the Staffordshire and Worcestershire Canal, to central Birmingham. Twenty locks (later 21) raised the level of the line through 132 feet (40 m) immediately after Aldersley Junction, and it then followed the 473-foot (144 m) contour, which later became known as the Wolverhampton Level, to Spon Lane, where three locks raised it to 491 feet (150 m) to pass over Smethwick summit, and shortly afterwards, six locks dropped it to the 453-foot (138 m) Birmingham Level, which it followed for the rest of the way to its terminus. Traffic on the canal increased rapidly, and the summit level was lowered in the 1790s, cutting out three of the locks at each side. At the same time, the remaining three Smethwick locks were duplicated, to speed the passage of boats.

As trade continued to increase, the Smethwick summit caused problems, both of water supply and of congestion, and so the company commissioned Thomas Telford to construct a new main line. This would follow more recent practice, using cuttings and embankments to follow a much straighter path, and the resultant main line, now called the new main line, shortened James Brindley's winding contour canal by around 7.5 miles (12.1 km) to 15 miles (24 km). The new line left the old line at Factory Junction near Tipton, and descended through three locks to reach the Birmingham Level. It intercepted the Wednesbury Canal at Pudding Green Junction, and created a straighter route to the bottom of Spon Lane Locks, which had previously linked the Wednesbury Canal to the Smethwick summit. At Smethwick, the summit was bypassed by a huge cutting, up to 71-foot (22 m) deep in places. However, the original line was retained and became known as the old main line. Work began in 1823 and was completed in 1838. Smethwick Junction was the point at which the old and new main lines joined, at the eastern end of Smethwick summit. The cutting and hence the junction opened on 18 December 1829. Bromford Junction served the similar function at the western end of the cutting.