On Fri, 17 Nov 2006 13:32:33 +0000 (UTC), (Andrew
Robert Breen) wrote:


In reality, these weren't going to be the first examples of tied arches
in railway use: the tied arch was first described in the early 17th
century (1617, in fact, by Veranscics[1]) and it is surely unrealistic to
expect that such a useful and economical type of bridge wouldn't have been
used for waggonways (in wooden form).

Robert Stephenson certainly used an iron tied-arch bridge in 1833 at Long
Buckby on the London and Birmingham railway[2] - so it's safe to say that
the TfL claim that the new ELR bridge is the first bowstring bridge to
carry a railway in .uk is but flagrant flapdoodle and blatant bosh.

[1] http://www.icomos.org/studies/bridges.htm
[2] http://www.robertstephensontrust.com/time.htm

Something wrong with [2]. Long Buckby isn't on the London to
Birmingham line. I believe there was a bowstring bridge on the L & B
but cannot immediately trace where it was.

Incidentally Byran Morgan's Railways - Civil Engineering refers to a
'diminutive' bowstring bridge on the Stockton and Darlington Railway,
parts of which are preserved in the NRM.
--
Peter Lawrence