Re: Curved bridge or tressle

=>I have a drawing of a deck girder bridge on the Espee. I don't know =>where it is located but... the bridge is straight, the track is =>curved. It looks a bit strange.

Well, maybe, but that's the normal way of doing it. To my eyes a curved grider bridge looks more than a bit strange. :-)

For the most part they still are. While it's possible to analyze and fabricate curved girders for railroad loads, there's generally no good reason to.

Chris Johnson

In article , "Dan O'Connor" by "Dan O'Connor" dropped his wrench, scratched his head and mumbled,

The asymmetrical loading at the center of each span must lead to enormous overbuilding of the stringers or some super elevation to keep the load on the center line between the stringers. Otherwise the angular moment would either tear out the bearing on the inner supports (bridge)or twist the bents out of the ground (trestle). Straight has got to be worlds easier, if not better.

Bob

On Mon, 30 Jun 2003 22:50:25 UTC, "Wolf Kirchmeir" wrote: 2000

As has been pointed out most track across bridges is straight. Seeing a curved track is a bit strange.

I also have a drawing of a curved trestle. The layout of stringers is quite interesting. Each stringer spans two bents. It is perpendicular to the middle bent. The next stringer is offset by one bent so that the space between the stringers is not uniform. Looks complicated but is not. The outside stringers are actually curved which makes the deck look as if it is curved.

Fellas, On a fan trip to Sri Lanka we went over a curved brick built viaduct, and I'm sure that there is another famous one on one of the Scottish lines, but are viaducts bridges? I reckon that they are, being a series of bridge spans. Regards, Bill.

That is the most common kind of curved-track bridge, and not at all rare. Most of them are quite short.

Mark Alan Miller

For a (not so good) photo of a train moving in such a bridge, you could see at

(the so-called "De Cirico bridge"). I hope this gives you an idea (not so unusual for a narrow gauge line which had to contend with extreme curvatures etc.)

Regards from hot and humid Athens (*NOT* the one in Georgia!), Nick Fotis.

There is a famous wooden curved uphill trestle in the canyou at highrolls between Almagordo and Cloudcroft New Mexico.

Jim Stewart

There is a famous curved viduct in Switzerland, and a less well-known one on the privately owned tourist section of the line through the Dordogne from Martel to St Denis. Nothing strange about them.

Dave

You are probably thinking of the Glenfinnan Viaduct on the West Highland Line. Its main fame lies not in being curved, which is fairly common on arched masonry or brick built viaducts, but in being built of mass concrete.

A Google Image search for "Glenfinnan Viaduct" yields about 60 images of which this one

archive/rh-99b07.jpg shows well the concrete and the curvature.

The contractor for the line, Robert McAlpine, later known as "Concrete Bob" gained his reputation by using that material extensively for bridges and some other structures. A brief history of the construction of the line is at

For a really spectacular curved masonry viaduct, have a look at

which shows the Landwasser Viaduct on the Raetian Railway in Switzerland. The track emerges from a tunnel mouth high up a vertical cliff face directly onto the viaduct. Again, a Google image search on "Landwasser Viaduct" will yield nearly thirty images.

Hope this helps,

Alex. W. Stirrat

Thank you for the post of the link to the Raetian photo. In the true literal sense of the word, that is awesome.

I had long ago seen a 3 or 4 part "travel log" on PBS of a sort of "circle route" trip in Switzerland of the meter gauge roads, and the Raetian was prominent in the shows, but there were no photos from below the Landwasser Viaduct.

Wow!

-- Jim McLaughlin

**************************************************************************** **************************************************************************** I am getting really tired of spam, so the reply address is munged. Please don't just hit the reply key. Remove the obvious from the address to reply. **************************************************************************** **************************************************************************** Special treat for spambots: snipped-for-privacy@ftc.gov, snipped-for-privacy@ftc.gov, snipped-for-privacy@ftc.gov

***************************************************************************

The more usual design is to have the arches with constant span, ie same on each side and make the piers take up the difference, ie the piers are not of constant thickness. Much easier to build like that. Keith

Make friends in the hobby. Keith Visit Garratt photos for the big steam lovers.