Except that’s not a Heavy Girder Bridge.Heavy Girder Bridge: On the 3 May 45 the railway bridge over the River Oste at Hechthausen in Germany was destroyed and would have been reinstated by Royal Engineers Army Troops and it is still exists today, seeking to confirm which unit built it, the railway from Hamburg to Cuxhaven was double track, however became single track before and after this bridge, Deutsche Bahn now intend to upgrade the line from Stade to Cuxhaven with overhead electrification and believe this bridge will be replaced.
HGB was a panel bridge; a giant Bailey. Panels were joined by pins and the panels had welded joints. Your bridge has riveted sections making up a continuous truss. HGB entered service in the 50s IIRC.
I believe the oldest equipment bridge still in use is the Inglis bridge at the entrance to Vauxhall plains in Monmouth. Still maintained by the MOD, it’s WW1 vintage.