In the Rochdale area, there is the historical matter of the Wellington Bridge, that was original built for carry heavy-rail double track when first constructed in 1882 by the Lancashire and Yorkshire Railway, which was the reason why TfGM held a feasibility study upon when the conversion of the line to the Manchester Metrolink system was envisaged. It was found that the required strength of the bridge decking to carry new double track slabs and rails was compromised by the condition of the existing bridge decking which lay 150mm below the sub-ballast in places.
It was reported back to TfGM that this posed severe technical challenges and doubts were expressed as to the ability for the existing bridge decking to carry the required trackwork infrastructure. Doubts were also expressed as to the conditions of the base ground bridge foundations.
With the unbudgeted costs to replace the existing bridge decking and for the bridge foundation refurbishments being a matter of project financial consideration, it was finally decided by TfGM that the solution would be that the new Manchester Metrolink where it passed over Wellington Bridge would be in the form of a single-track, bi-directionally signalled, that the existing bridge decking would support. It was stated that such a solution would not impact upon the operation performance of the new Manchester Metrolink system, which would see double trackwork reintroduced on the line from Shaw to Rochdale, which had been reduced to single track heavy rail operation for many years before the line closure for conversion.
).