Atlas/Roco Curved Cord Bridges

[beiland]

I've been a fan of these Atlas bridges for quite awhile, including when I put several of them on my first layout, the Central Midland. They are made by Roco of Austria, and are a fine quality product.

On that original layout I sought out a double wide modification, and in that particular case I did not include the bottom deck floor portions. I also double-upped on that upper bracing piece






Yesterday I was moving forward to add that upper connecting structure to my existing bridge,...only to find out that the existing one I have must have been built for a 2" C/L track spacing. Doubling that upper bracing structure would not work.

 

[beiland]

Construct a New Bridge
I would instead have to modify the track spacing to 2.5" track spacing and construct a new double track version utilizing 2 new kits.
I resisted this notion until I discovered that I had already provided for a 2.5" C/L spacing for my 2 mainlines down at the bottom of the viaduct up ramp.

New Bridge built
Here is the new bridge kit built,...now to fit it in.




Note how you see thru the deck now,...no extra support piece required underneath.

 

[beiland]

37 minutes ago · Edited

Funny how old subject threads of mine keep popping up. I was recently asking some questions about painting a couple of my bridges silver, black, or rust colored. This double-tracked Atlas/Roco one was one of them. I noticed I did not have the walkways installed on this bridge.?

So I decided to go visit my cargo trailer storage and see where I might have put them. Turns out I have a whole big box of 'bridges' of various sorts,....but I could NOT find those walkway parts. Guess I am going to have to savage them off of some other misc parts I seem to have for these bridges.

Atlas/Roco never made a double track version of the 'curved-cord bridge'. I sort of invented one back years ago when I needed a dbl-track bridge at the entrance to my freight yard on my old Central Midland layout,...as pictured in the opening posting of this subject thread,
and here,..




Turns out I actually created 2 of these dbl-tracked versions for that layout,...the silver one in the foreground that carries trains into the freight yard, and a black one in the background that existed on a dbl-track mainline back there,..
https://forum.mrhmag.com/post/the-c...mstrong-atlas-plan-29-12207702?pid=1331218382

 

[beiland]

On my new layout I have a bridge spanning a large log pond, and it is single track one. I had considered several other brands and manufacture's bridges for this location, including central valley and X brand, and a nice wooden one I had acquired,...BUT this track was going to be a mainline on that upper deck, thus needing to carry very tall double-stacks, and autoracks, etc.






Many of these other single track bridges would not accommodate those tall cars, so I have just had to fall back on the good old reliable Atlas/Roco one.,...another reason I like these bridges.

 

[beiland]

Just in case you didn't see it, I have used the 'decks and walkway pieces' of these Atlas/Roco bridge kits for other purposes as well. Again referring back to that early 'Central Midland layout' of mine, you might see where I used some of these pieces to build the bridge-decks of my turntable. They were set down on on top of 'upside-down' Atlas plate-girder bridges'








Early turntable experiments utilizing Atlas/Roco bridge deck pieces,..
https://forum.mrhmag.com/post/the-c...mstrong-atlas-plan-29-12207702?pid=1331277025

 

[BigGRacing]

Good morning Beiland,
the bridge in the lower right corner here, do you recall what the Centre to centre distance is on it, brand etc…..did you shave your bridges above to get the 2.5“ c/c track distance ?

 

[beiland]

I assume you are speaking about this one that crosses over to the turntable? That is a Walthers bridge with 2" centerline tracks. (I'm somewhat surprised that Walthers failed to give that dimension).

I think most of the dbl-track bridges from Walthers are 2" centerlines between tracks.

That black Atlas/Roco dbl-track bridge I had originally thought of placing on my stone viaduct was not built/modified by me, but rather one I acquired at some train show. When I went to put the top crossbeams ('upper bracing') into it I discover they would not fit easily,..AND I discovered that I had already planned on a 2.5" centerline distance for my viaduct tracks. That's when I went back and constructed my new dbl-track curved cord bridge. If you place the two singles together you get a nice matting top structure and the 2.5" tracks.

 

[BigGRacing]

Thank you, and yes, being sick I forgot to attach the picture. Your info was spot on though and greatly appreciated.

 

[beiland]

FAKE BRIDGES
Several of my bridges were not really bridges in the truest sense,.... they didn't have their bottom structures.

Both of these were the double-track bridges that I Ikit-bashed from single-track Atlas/Roco Curved Cord Bridge kits. I simply took two single track bridge kits and 'doubled' the upper connecting beam structure to effectively provide for a dbl track spacing between the curved cord beam structures.

I left the bottoms out (to be used on other projects*), and just relied on the roadbed to provide support for the track of the bridge. I glued four 'locating pins' onto the corners of the curved cord sides, and these plugged into 4 holes drilled into the roadbed. This kept the 'bridge' properly located, and its side frames properly spaced apart such as to not interfere with the passing trains.

One of these dbl track bridges was set up as a safety device,....that one against the backside of the layout right at the point of the crossover switching between the 2 mainlines. I had in the past experienced several of my nice steam engines derailing and crashing off the layout onto the concrete floor...NOT a pleasant experience!! I decided I was going to put up this bridge structure to prevent any derailed loco from experiencing that fall off the side. Strange as it might seem, after I put this 'guard-rail bridge' into place. I hardly ever experienced any other derailments ??

That 'fake bridge' precipitated the idea of a stream/river running under it and out into the 'country backdrop. It also meant I have to have another bridge for the inner track,....thus the 'double track bridge' to allow for variety.

The other 'fake bridge' came about as a result of my adding the Walther's double track truss bridge for the dual tracks I wanted to have enter into the turntable zone. Since I had that bridge actually spanning the lower tracks, its only naturally the my yard entrance tracks would also be spanning those mainlines below. The 'fake double chord bridge' was the easiest way to do this without tearing out the subroadbed and replacing it with an actual real bridge. Besides with all the ballast, and cinders, etc in this yard area, no one would ever tell there was no bottom on that bridge. I also had to pay particular attention to the exact location of those bridge side frames so as to not interfere with the swinging passenger cars and articulated Big Boy loco that would come thru that trackage.

 

[beiland]

So I decided to paint this bridge flat black. Now I want to add some walkways to it,..the ones that came with these bridge kits.

This is my question at the moment,...what do I do about the center strip between the tracks of this double version?
1) Do I just add a plain plastic strip down the center to hide those holes meant for the original walkways?

2) Do I double up the original walkways with their hand rails on the outside of that dbl walkway,..



3) Or do I double up those center walkways with their handrails back-to-back down the center of the bridge,..




There is only the slightest problem with choice #2, the handrails are only 3/4" from the centerlines of the tracks. In other words its equivalent to have 2 mainline tracks with a 1.5" spacing.

What do you think,..it could work either way??

 

[Bonita Grand Central]

So I decided to paint this bridge flat black. Now I want to add some walkways to it,..the ones that came with these bridge kits.

This is my question at the moment,...what do I do about the center strip between the tracks of this double version?
1) Do I just add a plain plastic strip down the center to hide those holes meant for the original walkways?

2) Do I double up the original walkways with their hand rails on the outside of that dbl walkway,..



3) Or do I double up those center walkways with their handrails back-to-back down the center of the bridge,..




There is only the slightest problem with choice #2, the handrails are only 3/4" from the centerlines of the tracks. In other words its equivalent to have 2 mainline tracks with a 1.5" spacing.

What do you think,..it could work either way??

I'd try then up the middle with the handrails next to the track where they would be of some use. If the trains don't get snagged on the hand rails then good. Handrails don't look right to me in the middle. Nice bridge.

 

[beiland]

I'm begining to think the same,..no handrails in the center.

I think just plate steel painted with a non-skid paint might be more prototypical

 

[Sirfoldalot]

I am thinking hand rails only on one side? Or, maybe not at all!
Wish my memory was better.

 

[ctclibby]

Lots of good ideas although I do not think I have ever seen walkways down the center of a dual track bridge. Too bad that you can not get rid of the plastic middle thingie and just be able to look through the bridge floor with ties in the center.

 

[beiland]

Lots of good ideas although I do not think I have ever seen walkways down the center of a dual track bridge. Too bad that you can not get rid of the plastic middle thingie and just be able to look through the bridge floor with ties in the center.

That's an interesting, idea, but likely VERY difficult to do with the way that bridge kit is constructed.

 

[Bonita Grand Central]

How about laying a plastic or wood sheet over the middle hump and paint it to match the bridge. I doubt anyone would be walking across a bridge like that using the middle walkway. It would be too dangerous.

 

[BigGRacing]

My choice is no hand rails unless it’s a newer era, I don’t think they would have had handrails back in the old days on a truss bridge

 

[beiland]

How about laying a plastic or wood sheet over the middle hump and paint it to match the bridge. I doubt anyone would be walking across a bridge like that using the middle walkway. It would be too dangerous.

Thats what I did,..no handrails in center. Photos coming after painting