On Mon, 23 Nov 2009 14:40:33 +0000, Mike Clarke
wrote:

wrote:

I remember one collapsing in the 1966 floods. An archer was employed by
teh GPO to get a line across for to pull telephone cables across. A bailey
bridge was built quickly by the military to replace it, and I think it's
still in use.

That sounds like the bridge over the Eden on the Alston to Penrith road at
Langwathby. http://www.langwathby.org/bridge.htm


That isn't a Bailey bridge. It is a Callender-Hamilton bridge.

The Callender-Hamilton is a very different beast. It pre-dated the
Bailey design. It is stronger than a simple Bailey bridge and can
carry heavier loads and/or span significantly longer distances.

However, it takes much longer to construct than a Bailey bridge
because it is made of many individual pieces of galvanised steel
bolted together with thousands of galvanised bolts which all need to
be torqued up. The Bailey bridge is prefabricated in panels which are
joined together with dowel pins - an instant fix. Only the cross
beams that carry the deck need to be bolted.

The Callender company later became part of BICC (British Insulated
Callenders Cables) which spawned the engineering contractor Balfour
Beatty. So Balfour Beatty holds the rights to the Callender Hamilton
bridge system while Fairfield Mabey holds the rights to the later
variants of the Bailey design.

The designer of the Callender-Hamilton bridge, Archibald Milne
Hamilton, successfully sued Donald Bailey, the designer of the Bailey
bridge, for breach of patent. However, it is fair to say that the
Bailey bridge's panel design was superior in that it allowed rapid
construction without needing heavy lifting equipment, which meant it
was much more successful as a military bridging system.

http://en.wikipedia.org/wiki/A._M._Hamilton
http://en.wikipedia.org/wiki/Bailey_bridge