Little noticed by the thousands of people who use London Bridge station, but above their heads are some of the oldest iron girders in the UK.
These girders can be found in the former Joiner Street that’s now the entrance corridor between the mainline station and the tube station, and if you look up above your head at the entrance, you’ll see the girders. They date from likely around the 1860s, as that’s when the railway station was enlarged.
Before that, Joiner Street was like any other street, open to the skies, and in 1839, the London and Croydon Railway built a railway station here, next to the existing London Bridge station owned by the London and Greenwich Railway.
The history of London Bridge station is confusing, to put it mildly, but the London and Croydon Railway had an entrance fronting Joiner Street. With the shuffling of ownerships and the like over the next few years, by 1864, this was now the entrance for the South Eastern Railway, and it was they who extended the railway line to Charing Cross and Canon Street.
So what had been a terminus station became the through platforms, and the railway had to be extended over Joiner Street — which called for the use of iron girders. The girders that had only just been invented by a couple of Londoners for use on bridges.
James Warren was born in Mile End and had a profession as a merchant. Although not a trained engineer, he gained an interest in developing an iron truss for bridges.
In August 1848, along with Camberwell born Willoughby Monzani, they patented the Warren Truss. The use of alternately inverted equilateral triangle-shaped beams gave the truss a lot of strength in both compression and tension, making it ideal for long spans. Other people had developed similar designs, but the Warren Truss was considered to be an improvement as it offered greater strength for less weight.
According to a sign put up in the London Bridge station entrance, the girders above your heads are the very same that were installed for the railway extension and are thought to be “some of the earliest surviving examples” of their type.
Today those triangular girder designs are commonplace, but in the 1860s, they were still fairly new. And not bad that over 150 years later they’re still up there doing the job they were designed for.
They were cleaned up recently as part of the Thameslink Programme’s redevelopment of London Bridge station, with support from the Railway Heritage Trust.
And, as a heritage sign nearby notes, the brick arches to the eastern side of Joiner Street (left side of the photo above) are also thought to be from the original station entrance built by the London and Croydon Railway.
Something to look out for when you’re next using London Bridge station.
The plaque, which was added in April 2019 reads:
James Warren (1802-1870) and W T Monzani patented their iron girder in 1848.
The triangular frams are cast iron, with a wrought iron bottom chord, and the Grade II listed trusses above this area are some of the earliest surviving examples.
The eastern abutment arches are believed to be the remnants of the 1839 London and Croydon Railway terminus station.
A propos of your photo, are they ever going to reopen those escalators?
Very much doubt it – when I walked past them before Christmas, all the metalwork and moving parts had been removed, just leaving concrete ramps.
Truly fascinating, thank you. I *must* remember to look up at them next time I am at London Bridge
Hi Ian,
I worked on London Bridge Station redevelopment and designed the strengthening of the rail bridge above. A few notes:
– The Warren trusses actually date from circa 1850. They were used as pedestrian access to the then terminal station (there was ramp access down from platform level to Borough High St).
-The girders are unique not only for their age, but that they are one of the only surviving examples of a composite wrought iron / cast iron truss. The trusses comprise cast iron triangles with wrought iron connecting bars. Wrought iron is used for the lower chord, as it performs better in tension (cast iron being notoriously fracture prone).
-While Warren patented his eponymous truss, these were actually designed by Peter W Barlow.
-The first section of the station opened in 1836, and there has always been an upper level walkway over Joiner St, though not the entire length as it is now.
-The bridge built in 1864 to carry through tracks is still in existence, and still carrying through tracks (one level above the trusses). It was opened as a twin through girder comprising built up wrought iron plates riveted to form I sections. A third (central) girder was added later in the century to improve the strength of the span as the weight of trains increased. The Thameslink plan required the tracks to be slewed across this central girder, which (along with it already being assessed as non-conforming to modern loads) meant the bridge needed to be replaced. Unfortunately that was impossible due to the short time available during the planned Easter Possession (track closure). We had to pivot to strengthening the existing span by inserting two steel plate girders under the existing span. This had to be done without touching the grade II listed warren trusses, so the girders were flown in sideways (web parallel to the ground) in several pieces. It was a very interesting project!
I’m happy to pass along the historic study prepared by Alan Baxter Associates which outlines the history of the station. It includes some great sketches and plans of the various phases of the station. Please feel free to drop me a line.
Very interesting. Thanks for the extra detail