Bridge Question

[BATMAN]

I am thinking of putting the Faller Bletschal bridge or a viaduct over this what will one day be a deep canyon on this section of my layout. It will go roughly between the two upright supports in this photo. (It is 60" between them) I will cut out the spline when the final bridge length is determined. What I want to know is can a bridge like this be put in and be made so it is removable or should it be installed permanently in place? I thought I would like to be able to remove it if I wanted to do some work behind it without the possibility of damaging it. Thanks Brent

[tomikawaTT]

I see no reason why the bridge, and the slice of landscape it stands on/spans, can't be built as a removable domino, securely anchored to the main benchwork when installed, but able to be lifted out after removing a few screws or bolts.

I have already built two yard throats in similar manner, and am about to embark on building another.

Chuck (Modeling Central Japan in September, 1964)

[Blind Bruce]

Is the Faller bridge really 60" long?

[BATMAN]

Blind Bruce

Is the Faller bridge really 60" long?

 

 

I think it's about 44" long. I'll cut the appropriate amount of spline out once whatever structure I use is complete and ready to be inserted.

                                                                Brent

[Beaver14]

Brent, With a bridge gap of 44", you need to look very carefully at the supporting structure/benchwork. At issue is track alignment over time. Especially with wood bench-work, expansion/contraction and moisture absorption have a tendency to put the two ends of such a gap out of alignment. When I looked at the image of the bridge on the Walthers site, I immediately thought about a favorite long bridge trick: Keep much of the spline intact but apply the bridge girders (the "steel" that immediately supports the track) as cosmetic sheathing on the side of the spline. Then build the rest of the bridge structure to either be permanent or removable. Paint the top and bottom of the spline black, lay bridge track, and very few will ever notice that you can't see down through the ties. The alternative is very substantial bracing and benchwork structure to attempt to maintain alignment. Good Luck! Beaver Bill

[7j43k]

I endorse Bill's concept. It's the way to go if you don't mind the pseudo-invisible spine.

Ed

[bogp40]

Beaver14

Brent, With a bridge gap of 44", you need to look very carefully at the supporting structure/benchwork. At issue is track alignment over time. Especially with wood bench-work, expansion/contraction and moisture absorption have a tendency to put the two ends of such a gap out of alignment. When I looked at the image of the bridge on the Walthers site, I immediately thought about a favorite long bridge trick: Keep much of the spline intact but apply the bridge girders (the "steel" that immediately supports the track) as cosmetic sheathing on the side of the spline. Then build the rest of the bridge structure to either be permanent or removable. Paint the top and bottom of the spline black, lay bridge track, and very few will ever notice that you can't see down through the ties. The alternative is very substantial bracing and benchwork structure to attempt to maintain alignment. Good Luck! Beaver Bill

 

A method to align rail, allow for expansion and also allow removal of the bridge, is to allow the rails of the bridge to extend a few inches beyond the abutments and anchor to the ties. If flextrack is used spikes can be used in predrilled holes. The method I use is to lay the rail on some wood tie,then transition to the flex. This stabilizes the bridge allowing excellent anchoring and allows for removal if ever needed.

These Central Valley bridge have the shoes resting on the abutments; the left is wood spline w/ handlaid, the right is flex on wood spline. The bridges are located by the method described above

This ME viaduct is also anchored the same. The ME bridge flex had ties removed to extend out beyond the abutments. This area is all Wather's/ Shinahara flex so I glue wood ties to the areas for spiking. The entire viaduct is removable if needed. These bridges have been installed for about 4 years now and there has never been any problems w/ expansion or any misalignment

The structural integridy must be maintained on the lower portion of the benchwork. If a deeper canyon is wanted, provisions to tie the sections together is critical.

 

[BATMAN]

 Thanks for the input. I have though about dressing up the spline with girders and making it look like a viaduct, but I really like the idea of being able to look down through the iron work to see the creek below. Humidity is not a problem where I live and the room is always at a stable temperature. I think a steel arch bridge is the way I would like to go. One other question is how sturdy are these bridges when built? I am a little concerned about the visiting rug rats taking a poke at it. Thanks.

 

                                             Brent