Snoopy, by coincidence, I was recently trying to help an ex-member of the Canadian Air Force's 400 Squadron about this incident. They celebrate their 80th anniversary in 2012 and are gathering information, images etc (including the one you posted) to celebrate the anniversary. I seem to recall that they want to build a scale model of the bridge to depict the stunt. The bridge in that picture was demolished in 1983 and was replaced by a concrete one, certainly interesting as bridges go, but not a patch on the original one
The incident occurred on 19.10.1941. As records couldn?t be found

, a calculation using a picture from the 1930?s, gave approximate height of the arch as 33?, and the width at mid-span as 44?. The wingspan of the Tomahawk was 37?, so it was hell of a squeeze.
400 Squadron still survive as a Canadian Air Force Reserve unit and flies the Griffon Helicopter from Can. Forces Base Borden (North of Toronto).
The picture below was created by Mrs J R Hitchcock in 1941. The guy I have been dealing with has managed to locate the artist and the son of the pilot (in Canada)
