I am planting three of Micro Engineering 85’ ballasted deck bridges together to span and area on my model railroad. I have constructed the abutments and am now going to work on the piers. I am not sure if I am correct in my understand that ballasted deck bridges generally were or are not used to span very long or deep area’s if you will. From the pictures I have seen they usually seem to be no more then maybe 20’ to 30’ above what ever they are traversing. Is this correct or have they been used to span areas where piers 50’ tall or taller are required?
Thanks your help and advice is always appreciated.
In the wilds of rural Tokyo-to, there is a truly magnificent ballasted deck bridge that I intend to reproduce on my layout when construction reaches that point. It’s a deep parabolic concrete arch on a curve, with the deck raised above the arch on vertical piers. From the deck to the rapids directly below is at least forty meters. The tallest piers, at the ends of the arch, are probably 25 meters tall.
What makes it even more `modelgenic’ is that the track comes out of a tunnel, goes directly onto the bridge deck (ballast under the ties, on a wide concrete platform) and then directly into another tunnel. The whole on a rather tight curve and a steep grade!
Ballasted deck bridges are quite common, and can be high. The UP’s new Kate Shelly bridge is a ballasted deck. It uses pre-cast concrete ‘troughs’ for the ballast. And the bridge is High & Long! Ballasted deck bridge offer the advantage of using normal track/tie structure rather than the special fastenings needed with open deck construction. Either ‘panels’ or ‘troughs’ are used to hold the ballast pile. They have been more popular in the past 2-30 years for new construction.
My HO layout has a 27" ballasted deck bridge that is about 9" high over a river. I built it out of the side girders from 3 Atlas plate girder bridges and a 1.25" square piece of maple. I used 5 minute epoxy to attaching the girders and ballasted the flex track in place. The maple can span the entire distance(the Mr. Plaster piers are just for show).
Almost forgot the truly huge, and high, masonry `Roman Aqueduct’ viaducts, Starrucca and Tunkhannock. Ballasted-deck bridges aren’t exactly a new idea.
Here is ATSF’s ballasted-deck, steel-viaduct trestle crossing Alhambra Valley in Martinez, CA on its mainline toward Richmond, CA. It now carries BNSF trains. The ATSF surely had the habit of using two Pacific-type locomotives at the head of its freight trains. By the way, the bridge is betwixt tunnels at either end.
Thanks for the examples guys the viaduct style bridge is not the type I was referring to but i guess it counts I was not aware of the ballasted tall steel viaduct bridge example just goes to prove that this place is a wealth of useful information.
That Alhambra viaduct is nothing more than a score or more linked deck bridges. Ballasted-deck railroad bridges are extremely common. Here’s an example of one crossing CA State Hwy 1.
