Yes Viv, the new line canal cut a straight path in to Birmingham. Built by Thomas Telford it removed the summit at Smethwick and three locks and it left the Soho loops that used to follow the contours.There may of course be artifacts scattered around that area from the building of the canal and bridge.
The canal line passing under Lea Bridge seems to be a 'new line'. Was that a new branch of the canal or a redirection ? In any case, the creation of this new route must have produced much industrial/canal construction activity in the mid/late 18th century, albeit it a little distance from the later infirmary/workhouse.