Need some advice on a bridge for the LIRR Industrial Service layout

[Lemosteam]

The picture below shows the elevated girder/trusswork and mainline trackage that will run from the berm wall (far upper middle right) across the canal, across the siding and all the way to the left "off" the layout.

The area I have been thinking about is the girder bridge in the foreground, inside the large red circle with simulated track underneath, representing the track in the small red circle in the background left, so imagine the bridge there.

Before answering the question below, please note the supports tied to the last cross brace and bridge shoes on the corners of the bridge.

Do you think the bridge looks "strong" enough without the temporarily taped on supports, or should I add them, with bridge shoes and lattice pillars (vertical yellow lines) like the rest of the trusswork?



I was thinking that it might add some visual interest under the open bridge, "parallel" with the siding where it passes under.  There will be a dirt road to the right of the siding, likely with some kind of aggregate hauling truck on it as well.

[up1950s]

What is an " IS " ?

[garethashenden]

What is an " IS " ?

"Industrial Service"
https://www.therailwire.net/forum/index.php?topic=28266.0

[garethashenden]

I think it looks better without the supports under the girder bridge. Girder bridges aren't built that way, if you want supports there you should really have three bridges, each ending on a pier. The long version of the bridge looks strong enough. Girder bridges are really strong actually, even though there's not much there. It's all in the height of the sides.

[Cajonpassfan]

Agreed, that looks like an eighty footer (?), plenty strong for a single span.

If I were to get picky, I'd say the railroad would likely not have used a *through* girder in this kind of a setting, unless it needed the clearance underneath. Deck bridges are cheaper, but require room underneath the track. Perhaps there is a road a few feet up paralleling the lower track requiring such a clearance?
Otto K.

[Lemosteam]

Otto, I needed clearance for the siding.  The taller boxcars would not fit under the trusswork alone.

[sirenwerks]

Are you running hicubes under it? By east coast standards, it seems high.

[Cajonpassfan]

Otto, I needed clearance for the siding.  The taller boxcars would not fit under the trusswork alone.

Well, there you go, looks good from this angle
Otto

[nkalanaga]

As garethashenden said, girder bridges wouldn't have intermediate supports like that.  If you want the supports, a three-span beam bridge, with two or three I-beams under each rail, would be more likely, and would give greater clearance.

For the girder bridge you have, if more support was needed, the railroad would replace the lattice posts and brackets under the ends with separate piers under the bridge shoes, leaving the lattice posts to support the elevated track.  But since the posts are adequate to support the other elevated sections, they'll also support the girder bridge. 

[Lemosteam]

Thanks to everyone who responded.  No extra supports!

[tom mann]

@Lemosteam where did the lattice posts come from? 

[wazzou]

I do question whether those little cantilevered corbels could support the weight of that bridge, much less a train on it.

[Lemosteam]

I do question whether those little cantilevered corbels could support the weight of that bridge, much less a train on it.

@wazzou , This was the gist of my concern as well, hence the question. One could assume there is a lot more structure under there- it will be fairly hidden under there.

The cantlievered load on the corbels would get partially transferred to the large beams on the other side of the cross beam and then down into the pillar at the ground.  I suppose I could sister another post down to the ground underneath the corbel bottom.

@tom mann ,  Took a hint from @David K. Smith a while back and used parts of a Central Valley N Scale bridge kits for the vertical posts.

See this page about halfway down.

[wazzou]

If I were to do anything, it would be to have some support more directly beneath those bridge shoes, be it doubling of the posts or some other way to go about it.

[Lemosteam]

Hmmm.  I could take those two extra cross beams and but them directly under the bridge shoes with some more posts down to the ground.  I think the differing heights of the crossbeams could be visually interesting at both ends of the bridge.