Does an Inclined Deck Bridge or Trestle Exist In Prototype?

Model Railroader Layouts and layout building
1

HI Guys:

Is there a prototype for either a deck bridge or a trestle on a grade? By grade, I mean an incline (or decline) of about 1.025% or more.

Thanks,

Timboy

2

That would be the norm whenever the track is on a grade.

This trestle is on a 3% grade:

Mark

3

We had a thread on this topic some time within the past 8-10 months, and it should turn up in a search in “Search Community” at the right sidebar. I’ll take a stab myself and come back to post it if I find it.

But it should be understood that the majority of all bridges are on grades, even if only 0.10%.

-Crandell

Well, I didn’t have much luck with the various search syntaxes I used. Anyway, yes, there are numerous examples of deck bridges on a grade. All the bridges and snow/rock sheds in the Rockies for the CN and CP lines are on grades. Any time a graded right of way encounters an obstacle of some kind that must be bridged or tunneled, the result and desire is to maintain the grade as closely as practicable. Footings are engineered and established, and the deck and rail heights too, and what comes in between is simply arithmetically derived in terms of the lengths/heights.

4

5

Thanks to all for your input and info! I figured there just had to be plenty of instances where this was necessary, but I wanted to be sure. I didn’t have much luck with a thread search on this either, but now I know. Nice pics, BTW!

Thanks again!

Timboy

6

At least one approach to crossing the Mississippi river on the Illinois side at St. Louis starts at grade and climbs to fifty or sixty feet on wooden pilings and bents.

7

Would this happen to be it?: http://cs.trains.com/trccs/forums/p/156839/1729999.aspx#1729999

8

Funny you should ask that. There is an article in the new issue of MR (Sept. 2010) about coal dumping trestles. Some of them were built on some serious grades.

9

If the bridge in question is a deck truss, the vertical frame members will still be vertical, and the normally rectangular panels will be parallelograms.

No matter what the grade, trestle bents and bridge piers/abutments will be vertical, or vertically symmetrical if tapered from bottom to top.

If you visit Steamtown, the walkway from the parking area to the mall across the tracks is built on the grade and footprint of the coaling trestle that once stood there.

Chuck (Modeling Central Japan in September, 1064 - with a number of deck bridges on grades)

10

Wow, good for you! I hadn’t thought of using the word ‘truss’ in my search, but that is the thread I had in mind. Somehow I had inflated it over time to be more lengthy than it obviously is, but at least my answer is consistent. [:D]

-Crandell

11

Tch, tch, tch. Amateurs. (LOL) And you should be ashamed of yourself. There were six replies to that old post, and three were from you. Guess you didn’t think of searching using the “posted-by” option either! (more LOL)

Actually, to be fair, I didn’t use the word “truss” in the search. I just used “bridge”, and expanded the search period to go back a year, time flying and all that. Then I had to wade through all the non-related articles where “bridge” came up, including the bridges of the electrical sort. But I was at home watching the flight status of a plane so that I’d know what time to go to the airport, so I had some otherwise non-productive time to to kill.

Regards!

12

Here’s one.

13

Yes, Tim, for example on the BNSF (ex GN) line up the Cascades in Washington state the Foss River Bridge is a 7 span high viaduct with a compound curve on a 2% grade. The curve varies from a 10 degree railroad curve on the higher east end, transitioning on an easement to tangent at the lower west end. This looks beautiful if you have room for large radius curves. I use 60" for this bridge, but a scale 10 degree curve is about 88" radius in HO. John

14

Terrific response, guys. I now have a solid gold approach to work from when the time comes.

When I get that far on my current build, I’ll post some pics showing my versions of inclined support.

Thanks again for the info and for the pics as well.

  • Timboy
15

There are several inclined sections on the Chicago elevated system where the L tracks go over elevated railroad rights of way. Two notable locations are on the blue line between Western and Damen, and on the brown line between Addison and Paulina. This incline is on a 90 degree curve.

The L tracks are very long deck girder bridges.

16

timboy:

I’m probably ‘taking coals to Newcastle’ as my grandma used to say, but I can add that if you’re ever up here in the northern part of California, just about every railroad going over the Sierra or the Cascades has numerous bridges, all on grades of from 1-2% (and some even a little steeper).

On my own Yuba River sub, out of 13 bridges, only one is on a level tangent, the others are all on grades of 2-2.4%. In fact my tallest and longest bridge, the Deer Creek Viaduct (4’ long, 18" high) is on a 2% grade with a 36" radius curve.

As several other modelers have commented, seeing photos of it: “It’s SCARY!” LOL!

Tom [:)]