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Old June 27th 19, 06:52 PM posted to uk.transport.london
Guy Gorton[_3_] Guy Gorton[_3_] is offline
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First recorded activity at LondonBanter: Oct 2013
Posts: 75
Default Cockfosters depot WW2 pillbox

On Thu, 27 Jun 2019 13:38:13 +0100, Basil Jet
wrote:

On 27/06/2019 11:48, David Cantrell wrote:
On Tue, Jun 25, 2019 at 04:02:38PM +0100, Guy Gorton wrote:

The only links Gatehampton has with transport.London is that the
Thames is flowing towards London and the railway is running away from
Paddington! But that is my excuse for mentioning this lovely viaduct
by Brunell which was built at two diffrent times, using different
brickwork techniques, the two being attached to each other their full
length.


The Grosvenor bridges crossing the Thames outside Victoria were built
similarly, one track at a time, so that the old structure could be
replaced without having to close Victoria station.


I've always wondered if there is any advantage in having a multi-track
bridge as opposed to several single track bridges with inch gaps between
them. You'd think narrow bridges would be preferable with respect to
maintenance, and also preferable in most conceivable catastrophes, but
one wide bridge seems to be the usual choice.


Brunel used both. Maidenhead is the first going west and it was made
by extending the existing spans on both sides. Very interesting to
look at from underneath the river arch. Quite distinct differences in
the constructon techniques. Gatehampton is two bridges glued together
so that at rail level there is no break. The next set is at Moulsford
where there are two independent viaducts with some construction
differences and some connecting mini-arches. Other Brunel bridges
over the Thames demonstrate his versatility - wrought iron at Windsor,
steel on the Henley branch, steel(?) at Bourne End, although the
last-named is probably before his time, it being on the Wycombe
Railway.

Guy Gorton