Large Scale Central

Curved track on a Deck Truss bridge

Track and Trestles
#1

OK guys, here’s what i need to do. I’m building about 12 feet of trestle on my mainline loop, part of it goes over the small lake/river(real running water). I’ve settled on a piling in the lake for center support, which leaves a bridge section span of 31 inches. This loop is a 10’ diam. curve. I want to use a decked truss bridge. My plan was to use a span of 7 inches wide, made up of 3 trusses to handle the curvature. Heres the single biggest question, Will this work? And if so, how would the decking, stringers, ties be laid out on the curve on top of a straight bridge? 2 or 3 stringers? or no stringers and 7 inch ties closely spaced across the top of the trusses?

BTW 1:20.3, code 332 stainless, track 26" above water line.

#2

(http://s615.photobucket.com/albums/tt235/danielpeck/May%20train%20run%20and%20update/?action=view&current=IMG_0909.jpg)

Would something like this work?

#3

Damn that is a nice bridge. I would worry about my junk jumpin the track and ending up as the final photo at the back of Garden Railroad.

#4

Thats the concept, But it’s kinda hard to bend wooden trusses! I suppose that I could lay them up like Glue-lam beams.

#5

Just add Truss under the girder and there you have it done. If you have to build the truss bridge, build skew with the long side of the curve longer and thus maken a radius. I hate to say that is one of the not so tall bridges I built…

#6
daniel peck said:
If you have to build the truss bridge, build skew with the long side of the curve longer and thus maken a radius.
:)
#7

I decided that sence I fairly new to this that I would build the bridge section wider then normal and then let the track curve on the top of the span. To make it wider then normal I decided to use 3 trusses wide. Got them built, and ready for the top decking.

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/photo.jpg)

Tonight I’ll see about getting the decking on.

#8

Oops didn’t get both images on that post. Another view.

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/photo_1.jpg)

#9

Looking good sop far Dave. If it’s a short span,with only abutments on the end, that’s about how the prototype would do it. You could still skew it to the curve by cutting the ends at an angle.

#10

Cool…will you have it in place on the layout this weekend?
:slight_smile:

#11

Nice looking start

#12

I’ve been hauling boxes of christmas stuff out of the basement, somehow the wife thinks that it’s more important then the bridge right now, Go figure!! Maybe latter tonight I’ll get to the decking…

#13

good looking start…

#14

Yeah… Got the decking on tonight…

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/photo_3.jpg)

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/photo_4.jpg)

Now to start on the abutment bents. 2 sizes, shorter for the bottom of the truss and taller for the top. These will have to be wider then my normal bents to fit the wider bridge. I have a couple of ideas on how to make it happen, but your input would be welcomed.

#15

Got the christmas tree up and had some time so i tackled the abutment bents. These are wider at the top to hold up the wider bridge then my normal bent. Got them made last night. Two heights, for the upper support, and the lower support.

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/photo-1.jpg)

I solved the added width issue by adding another pair of legs to the outside of my normal bent, And beefed up the top support beam, and the bottom sill also. Once I figure out the final spacing between the two, I’ll tie them together.

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/photo_1-1.jpg)

I need help here guys. I’ve never seen a prototype wooden pier to support the center of two spans. Would it be something like 4-5 bents closely spaced and tied together? I’m leaning to the wooden Pier, but open to other Ideas.

#16

Depends on the load it’s supporting, but yeah it would be reasonably prototypical to have a two or more bents close together supporting the center of two spans. It’s often done that way on the ends of a span too.

#17

Thanks Ray, I got the two extra wide bents for each end done. Would they be the Standard bent design, or more of a vertical pilings, sense they will be setting on a pier in the lake?

#18

Christmas over and I got back to the three truss bridges to span the lake. Got the three trusses for the middle span laid up. Some decking tonight and should have the 26" span completed… Still don’t know what I will Do for the pier between the two… rock, concrete or wood, a few tips here would be helpful.

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/Bridge-20001.jpg)

#19
Dave Taylor said:
Still don't know what I will Do for the pier between the two.. rock, concrete or wood, a few tips here would be helpful.
Dave, You seem to be doing just fine without any help ;) Ralph
#20

Got the decking today, this is the middle of the three spans.

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/Bridge-20003.jpg)

This show a bit of what I’m trying to do with these spans.

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/Bridge-20004.jpg)

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/Bridge-20005.jpg)

Tonight I’ll start on the third span, it’s short only about 12".