|Location Map ( geo)|
|Lancashire • Cheshire|
| 1963 (1st Span)|
1995 (2nd Span)
|Crossings related to the M6|
|Linstock Bridge • Lune Bridge • Metal Bridge • Mossband Viaduct • Samlesbury Bridge|
Thelwall Viaduct carries the M6 over the Manchester Ship Canal and the River Mersey near Warrington, crossing the traditional boundary between Cheshire and Lancashire as it does so. It originally opened in 1963 as part of the Warrington to Preston section of the motorway (now junctions 20 to 29). As the A50 and then A49 was still the major route to the North West at this time, the M6 here provided considerable relief for the A49 north of Warrington. As a consequence, the viaduct was destined to be busy from its opening day.
The original construction featured three lanes in each direction although there were no hard shoulders. There were distinctive railings alongisde the edge of the carriageway painted in blue and white. At the time it opened it was the longest road bridge in the country, although within twelve months it was dwarfed by the Forth Road Bridge on the A90. Whilst it was an absolutely impressive feat of 1960s engineering, problems soon became apparent. By the 1980s, the steep approaches and lack of hard shoulders were a major capacity problem. The fact that the M62 and M56 crossed the M6 a few miles either side of the junction also meant lots of traffic was switching between the two routes to access various parts of Manchester. Congestion became routine and the stress upon the viaduct was immeasurable.
In the early 1990s, widening works commenced to eliminate the problem. This required a new viaduct span to be constructed alongside the original 1963 span. Shortly after the completion of the new viaduct, traffic was routed over onto that structure whilst the old one was renovated for four northbound lanes. Unfortunately, after the works were complete it became apparent that the bearings of the 1963 viaduct were worn beyond repair and had to be replaced during a lengthy construction contract between 2001 and 2003. This meant severe congestion in the surrounding area whilst works were carried out.