Spon Lane Junction, between the Old Main Line and Spon Lane Locks, is an intimidating place to start. The M5 looms above and you're surrounded by huge supporting pillars, the 20th towering above the 18th century. With the canal and motorway playing cat and mouse, the start of the walk couldn't be a more urban landscape if it tried and, at the Stewart Aqueduct, the Old Main Line, New Main Line, West Coast Main Line and M5 form an adjacent if not entirely symbiotic relationship, reflecting canal mania, railway mania and present day road mania.
The underworld below the motorway not only resembles but actually is a dark desolate wasteland, you come up for air now and again but it's not until after passing Oldbury Junction, where the Thomas Clayton tar boats were based, and the Titford Canal departs through Oldbury Locks for Titford Pools 2½ miles away (see Titford Canal walk), that the shackles of the M5 are thrown off. The outlook however continues to be unremittingly urban, with modern factories or rather 'industrial units' as far as the eye can see. The towpath deteriorates and you can tell that this is the Wild West (Midlands) by boats flying the jolly roger.
After crossing Seven Stars Bridge, on the far side of the canal there's the remaining stub of the quarter mile long Houghton or Chemical Arm and Valencia or Valentia Wharf. The arm was once used by boats carrying materials and waste to and from Albright & Wilson, Chance & Hunt and other chemical works where all kinds of nasties were manufactured including phosphorous, ammonia, cyanide and TNT, and the site became a major munitions producer during World War II. The arm is now mostly filled in but what's left and the surrounding land contain so much toxic waste you wouldn't want to light a match close by! For many years, 1951-1997, the wharf was the site of Les Allen's boatyard and was part of a cluster of five basins opposite the southern end of the former Oldbury Loop which was by-passed in 1821 when the main line was straightened and finally closed in 1960. The northern end can be discovered about 700 yards further on but takes some effort to discern.
The next section is through a landscape that was once dominated by clay pits and brick works, modern factories are now on the far side and a few broken ones on the tow path side with new homes attached to satellite dishes appearing before Brades Bridge. This is not an unpleasant walk as trees on both sides mask the surrounding industry. The Gower Branch leaves the Old Main Line at Brades Hall Junction to connect with the new main line half a mile away at Albion Junction, and lock geeks will be excited by the top two Brades Locks which is the only 'staircase' on the BCN.
Herons enjoy looking for lunch under the appropriately named Fishers Bridge but, unfortunately if you want to admire them, the adjacent bench has been set on fire. You'll notice the canal narrowing at the Tividale Toll Stop and about half a mile later the Tividale Aqueduct takes the canal over the Netherton Tunnel Branch. Here you have to descend the embankment and go left towards the tunnel's northern portal.
Regarded as the last 'proper' canal tunnel to be constructed, the Netherton Tunnel was built to relieve congestion through the parallel Dudley Tunnel which was choked with traffic. It has the largest bore of any canal tunnel with towpaths on both sides and was completed in 1858, having taken just under two years and 53,000 cubic yards of puddling clay to construct.
It's 3027yds long and, although originally lit by gas and then electricity, very dark. The only intermittent light comes from the seven remaining ventilation shafts. The towpath can be very wet, in places like a stream. The spot of light in the distance doesn't get larger very quickly but at last you get to the other end and emerge near Windmill End Junction with the Dudley No.2 canal. Years ago the outlook was similar to rest of the Black Country, and the Cobb Engine provides a clue, but there are now nature reserves instead of collieries.
If your want to continue through Bumble Hole Nature Reserve to the famous Ma Pardoe's pub, refer to the Coombeswood – Black Delph walk.