Union Street Bridge (Ancoats)
1903 'UNION-STREET, ANCOATS. When the laying the track of the Bradford-street section the Corporation tramways was decided upon, it was considered desirable that the bridge carrying Union-street over the Rochdale Canal should be widened and strengthened. The roadway was narrow, the levels bad, and besides heavy vehicular traffic using the bridge the roadway was utilised as a canal tow path. By arrangement with the Rochdale Canal Company a new bridge, 47 feet wide, in lieu the old, 36 1/2 feet wide, which was erected in 1844, has been erected over the canal. The old towing path in the tunnel at the back of the abutment has been done away with, and a new and more satisfactory one provided. The levels of Union-street between Great Ancoats-street and New Islington have been raised and considerably improved, the whole of the new work relating to the canal was carried out in Whit week, when the water could run off without interfering with the traffic.'[1]
The 1903 rebuild work was carried out by Andrew Handyside and Co.
1903 photo here shows the bridge during reconstruction. It will be seen that the bridge carried an hydraulic water main. More photos here and here[2]
The 1903 rebuild featured riveted plate beams, and parapets assembled from cast iron plates. However, referring to Figs 1 & 2 above, we see a fairly low cast iron parapet bolted to a cast iron beam, with a higher parapet behind. Between the high and low parapets is a towpath. It rises from the canalside towpath via a spiral ramp, and crosses the bridge to Union Street (now called Redhill street). The presence of an arguably obsolescent cast iron beam begs the question of whether parts of the 1844 bridge were reused. In fact this cannot be the case, because the present beam is nearly 60 ft long, whereas the 1849 O.S. Town Plan shows a span of only about 40 ft. Reference to Fig 3 indicates that there is another cast iron beam a short distance inboard. One possibility is that the cast iron beams were indeed made as part of the 1903 bridge, cast iron being cheaper and adequately strong for the towpath portion of the bridge. However, the 1849 O.S. Town Plan shows that Union Street went straight across the canal, heading in a north easterly direction (the canal having a dog leg here). The 1893 map here shows that the bridge had been altered, being widened and aligned east-north-east with New Union Street. It therefore seems likely that the bridge had been altered between 1849 and 1893, and that the cast iron beams date from that period.
Figs 4 & 5 indicate the complexity of the bridge structure. The main spans have two pairs of fairly deep riveted beams, one of which can be seen in this 1903 photo. Between these pairs of main beams are numerous riveted I-beams (Fig 5), set at an angle to the main beams, but more or less normal to the masonry abutments.
The arrangement of the towpath over the bridge can be seen on this Google Maps image.