Triple track curved bridge: N scale


videobruce

videobruce

Tower Operator
I need to build two bridges on a curve that are triple track. Track is Peco code 55 flex. I plan on just spreading ballast over the plastic base of the spans, no cork roadbed.

One is short, around 6" in length, not a huge problem. The other is 16" in length that will have a offset center support. I plan on using 1/8" black ABS plastic for a base and custom extended length sections of Peco truss girder bridge sides (NB-38) for the upper support. Not any prize winner, it surely won't make the cover of MR.

Attached are photos of the two bridges from the side and aerial shots with the longer span with track in place. The trusses you see have not been lengthened. Nothing is attached or secured, just placed there for a overall idea what it would look like. That curved turnout is a approximate location on the short span. I'm also think since I have ample of vertical clearance of adding I beams or some type of narrow channel below. Also, that white center support will be changed due to lack of side clearance. It was a piece of 3/8" ply scrap left over from the table.

Question; will running traffic over a plastic base as what I plan be overly noisy w/o any cork roadbed?

Questions? Suggestions?

For photos see post #29.
 
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50 some views and no input??

In the 1st post, those section of side trusses are not the full length that I would use. I would 'kit bash' them together.

2nd choice; From a Atlas single track truss bridge. The pieces are just 'sitting' there, they would have to be cut down in length.
Though, I don't know what to do about the top cross supports.
 
It would probably make some noise... you could try gluing foam or something to the underside of the bridge to dampen the vibrations. Wouldn't be hard to test. :)

The mockups look good... dunno what the prototype does with the top braces. I'd be inclined to just double up the trusses and leave the upper braces out.
 
One other item that doesn't look right is having a switch before the bridge instead of after it. The real railroads would do all they could to avoid putting an extra track on a bridge in a situation such as that.
 
Can't really do anything about that since I need a siding as long as possible. If I place the turnout after the span, I reduce the length considerably.
We have a overpass at the west end of the yard that is full of turnouts! I would have to count, but I bet there are at least six. The width is as much as the length. It spans a four lane street on a curve.

A suggestion was to use a HO scale plate girder for the span. I would think it would look too far out of proportion.
 
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Would it be possible to separate it into multiple bridges? To imply they had a single track, then business took off and they needed more track through there so they build another bridge.

You could even use girder for one and truss for the other.
 
I understand about the lack of real estate! Guess that's just another situation where we bend the "rules" a little. I know I have, plenty of times.:p
 
Would it be possible to separate it into multiple bridges?
Click to expand...
I would like to, but I don't see how. It would just add more complexity to the list. Then I still have the problem with the spans, one, two or three tracks the 'appearance' problem is still there.

Back to plan one with the lengthened trusses as shown in the 2nd shorter bridge. This is a no go?
If so, how about plan two with the high trusses salvaged from two Peco single track bridges? The sing;le track bridge looked great, but it's debatable this way.

Plan three; this was suggested which seems to have possibilities, but it is HO scale;
http://www.shop.cvmw.com/72ftPlateGirders-2-1903-1.htm

I have a little room below for some type of support. I was thinking about this, but it is HO scale also;
http://www.shop.cvmw.com/BoxGirders-5-19025.htm
 
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Here are the dimensions of that 'base' for the span. Vertical clearance is 2 3/8" as it is now (not to scale).
 
I think you should take another look at the multiple bridge idea. A single-track bridge and a separate double-track bridge would be more believable (in my opinion) than a big triple-track bridge.

The Walther's N-scale through plate girder bridge can be built as single-track or double-track. It is fairly easy to kit-bash a few of them into a curved bridge. I've done just that to make a single-track curved bridge on my layout.

- Jeff
 
You'd definitely have to put a bit of space between the tracks to accommodate the multiple bridges, but having the three sets of track not be perfectly parallel would enhance realism again. Perhaps the inner two tracks could begin their curve earlier and the outer track could run straight a bit longer before entering its curve.
 
A single-track bridge and a separate double-track bridge would be more believable (in my opinion) than a big triple-track bridge.
Click to expand...
I agree, but I can't see how to do that easily w/o major surgery to this area.
The inner track is the passenger siding. The outer two are the mains. The left side is up against the wall, it runs almost the full length of the room.

Here are some more pics from different angles of the 'problem' area.
 
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Ok, here is what I hope is the finished product. I used CV HO scale plate girders (per recommendation), trimmed to length. I also bought some of their trusses for the offset middle support on the longer bridge.

I plan on getting those stone plastic 'panels' (assuming I can find what I like) for the 'walls' of the abutments to attach to the foamboard under each side of the spans. The clearance is somewhat excessive, as I seem to have a bad habit of going overboard on clearance as I did on my first layout. I decided to use 3/16" clear Plexi instead of that black, thinner ABS plastic for strength, but mostly so I could attach those plates to the side of the base. I also added strips of ABS that I cut for additional surface area to glue along the inside of the bridge for those plates. Those will be covered with ballast.
I also sliced the foamboard so the surface of the bridge base is level with the rest of the layouts foamboard and will use cork roadbed across the spans covered with ballast so no one will see the clear Plexi.
 
The plate girder bridge is by far the best look to me. The width of the three track span seems too cumbersome for any sort of truss bridge. I think you've found your solution.:D
 
Those sections of open truss girders didn't seem to look that great. Granted, I'm still not quite happy with it, but due to the width, curvature & length, I'm kinda limited. I'm also not a scratch building kind of guy. :(
 
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