No, that’s still a single level bridge. It’s a series of wood trusses, with a trestle approach at the close end.
Due to the style of construction of a trestle, with bridge beams laid on pilings, it is just simply not possible for it to be anything other than a single-level bridge. If you want two levels, the bridges need to be side-by-side, or of a completely different construction.
based on the concrete (? stone?) supports that are constructed, and the way that the trestle seems build AROUND them, I’d wager a guess that this photo is of the bridge whilst it was still under construction…
Stretching this interesting post a little…was there ever a dual track wooden trestle?I’ve been looking for pics of one on Google a while ago and couldn’t find any…all the trestles I found were single track.I have one planned for my layout,so it will likely be “one of a kind”.
Possibly there was such a thing, but it would have been very very rare. Where I have seen multiple tracks crossing a small stream, each track had a separate low pile trestle. Where a more major bridge was required, the usual practice was to have a short stretch of single track, or in some cases gauntlet track. The reality is that if traffic became sufficiently busy that the single track was a major bottleneck, the railroad could also justify the cost of more permanent spans of steel and/or concrete construction to replace the old single track trestle.
While trestles were relative cheap to build, those initial savings can soon be wiped out by the ongoing extra maintenance required. And replacing a structural member in your theoretical double track trestle would require both lines to be shut down.
John
I believe this is the trestle accross the Yolo Bypass west of west Sacramento. It is still there but the is slowly being replaced by concrete.
zps2e44de08 by Donald Schmitt, on Flickr
Here is a quickly inked diagramme of the double-wide I was describing earlier. It has separate bent frames, but shared sills.
nice… while it wouldn’t be “prototypical”, you could probably make a few tiers of that in a helix or something…
There was a long double-tracked trestle across the mud flats/rice paddies east west (corrected) of the Sacramento river on the old SP (now UP) route used by Amtrak. It was retained because converting it to a fill would have dammed the river in flood right where the backup would have poured into downtown Sacramento (and the SP shops.)
Some years ago a major court case in New Jersey centered around excessive speed onto a double-track trestle, a shoo-fly around a bridge under repair. A model of the scene was essential to the final decision.
When the railroad needed a double track trestle, they built a double track trestle. Repairing such was no more inconvenient than repairing a double track through truss.
As for multi-level trestlework, Mark Pierce has posted a photo showing a three-step switchback on a single huge trestle that was built just west of the Beiber leg of the WP’s Spanish Fork (Keddie) wye. It was temporary access to the bottom of a canyon too steep and unstable to permit any kind of earthworks below the WP tracks.
Chuck (Modeling Central Japan in September, 1964 - with not a trestle in sight)
I think you mean the trestle over the Yolo Bypass west of Sacramento. It is still there, but the railroad has been replacing the wood with concrete as the wood members need replacing. The trestle may have been built to the Standard Plan I posted. As of July 2011 (google street view) it is still mostly a wood trestle. By the way concrete caps look strange on wood bents.
This Is close to the Wood Trestle 2 Level Bridge that I have in the photo Gallery. It’s is in “Z” Scale model with two trains on it, upper train was 0-6-0 pulling two log cars and the lower level was a diesel engine pulling two box cars, I’m still working on it. the first level is at 100 scale feet the second level is at 60 scale feet.