I need to build a bridge to cross over another train line and possible a 2 lane road. It is on a curve and do not know how to build one. any suggestions? I am running HO scale if it matters.
I have no idea how I got the pic on the post, but I am thrilled.
I love bridges. That is a great site. You could scratch build a wooden trestle. The Kalmbach bridge book has good directions as well as a couple of threads here.
A truss bridge kit would be nice if the track is not too curved. A steel trestle would look great. There are several kits. If you don’t have the Walthers catalouge, this is a good to to get one and drool over the thousands of opportunities. Don’t rule out the german kits, they can be made to look great ,
two examples.
Have fun and post more pics
ARTHILL, Your pics always look great! I noticed on one of your pics you used what looked like a piece of 3/4’’ plywood. are you planning on painting the sides or do something different. Thanks for all your replies.
I’ve seen pre-built wood trestle supports at my LHS. They looked pretty good. On a curve, that’s about the only thing that will really work well.
First I suggest going to http://www.railpictures.net/index.php Look down the left column to categories… first is bridges and trestles. There’s pages of them, big-small, straight-curved.
The H0 reference tells us where to point you for models/parts… basically walthers catalogue.
What you need to work on (that would help us) is the length of the spans… you appear to have one pier between the abutments. Depending on the total span you don’t necessarily need this… except that the track is curved.
As a rule only masonry and stone viaducts and trestles are curved on railroads. (I just bet someone will come up with an example to prove me wrong).
You can combine one of these with a steel span… that pic site will show you how.
Steel spans, whether they are trusses or plate girders, get around curves in multiple spans as a series of straights. These are usually equal length cords.
In some cases the engineers use a string of skewed spans (i.e. not-square spans). In others they use square spans and change the angles at the piers… this is usually for the larger radius bridges.
It is possible to use one or two long(er) straight spans and lay the track in a curve on them. At the least the span has to be wide enough to accept the structure gauge around vehicles standing on the track at both ends and the maximum offset (which would usually be in the middle).
(You have to provide the structure gauge… that is the hole through which stock built to the loading gauge will pass… allowing for overhang at the ends and undercut in the middle of long cars. if you build your bridge to the loading gauge cars will only just squeeze through it (or stick) in a straight line. NOTE, if you are using severe curves - worse than the real thing - you need to compensate and increase the clearance to BOTH sides… easiest way to determine how much to allow is to get an 89’ car tape pencil right at the four corners
Mike, 80% of my layout is still basic bench work. I am adding scenes as I go, but it takes a while, I am slow and I like to run the trains.
You might laugh at this, but it works. I’m using it on my new layout. Life-Like makes a plate girder bridge kit with the piers. I pitch the piers (who wants those cheap things anyway) keep the plate girder bridge sides. There made to use with straight track, but I cheat a bit. I heat the bridge with a soldering iron and carefully bend it to the curve I need. I’ve done this Twice so far. It works. You might want to consider it.
mikesmowers,
Most modern bridges that have a curved rail are nothing more then short, straight sections of bridge joined together to allow the curved rails to pass over the top. sometimes the bridge is wider then normal to allow for the curved chord of the track.
This site might give you some ideas; http://pghbridges.com/basics.htm
And Jeffrey,
read the above, and if you still want to bend your bridges, might I suggest a hairdrier and some oven mits. Much less chance of disaster and since the heat is more spread out it is far more controlable IMHO.
What radius is the curved upper track? From the pic it looks like you need to span a good 60-70’ from the abutment to the center pier and about the same for the area of the future road(left). If the curve is 42" radius or larger, you may want to use the new 85’ Micro Engineering girder sections. The other HO lengths are 30 and 50’. ME also has a bridge flex track (code 83 36" long).
Other options are to use the Central Valley plate girder double track bridge (accomadate the curve clearance). I am suggesting more of the modern style bridges from the newer equipment you seem to run.
A quick fix is to add plate girders to the sides of the subroadbed. It may take some work attaching them. When I know that I am using the plate girders, I cut the plywood subroadbed to accomadate the bridge sides. You will have to work backwards if doing this option.
A wood structure with bents/ supports will not work due to the sharp angle of the crossing- a skewed wooden truss w/ a stone center pier may work but may be out of place for your period. If you use cut stone for the abutments, you should also use it for the pier. Same for concrete etc.
I hope all these options have helped and not confused you even further.
Bob K.
Since you asked, I’d take the easy route and not remove the track you have now. Get some Micro Engineering 30 foot Bridge Plate Girders (50 foot shown for example) and glue them to the sides of the sub-roadbed, starting from the center and low enough to hide the sub-roadbed from view (but first paint the underside of the sub-roadbed flat black). The idea is to make it look like a through truss bridge with a ballasted deck.
You could glue on I-beams under the sub-roadbed if you need to add detail. Attach bridge shoes to the bottom of the girders. Pick out some bridge abutments and install them by cutting out a section of the scenery under the ends of the bridge. The pier can be covered by wraping it with .005 styrene and painted concrete color. Or replace it with a casting.
I don’t know if this will work for you but it did for me.
Both bridges are pieces of bachmann EZ track with the track taken off. I flipped it over and filled it with plaster. I plan on balasting the track in the future. This kind of bridge is often used over short distances, I’m not sure about a longer one
Sounds like a wizard idea!
CSXFAN: This looks like a good idea, i may try to do just that since I have several pieces of old Lifelike track around and can’t think of another use for it. The curve on the upper track is a 15’’ radius.
I’m glad I could help. It was actually very easy to make. I haven’t figured out a way to make the underside of the bridge look better, you can still see the imprints of where the ties were. It should be easy to do though.
Good luck!
I needed a bridge on a curve also. Couldn’t find what I wanted so scratchbuilt my own. This is my first attempt at scratchbuilding. I did have a little help. Worked for State Transportation Department. We built a railroad bridge over highway. I used the bridge plans for my basic design.
Click on the link and the photo will open in another window.
http://i9.photobucket.com/albums/a59/moteel/100_2809Small.jpg
http://i9.photobucket.com/albums/a59/moteel/100_2805Small.jpg
http://i9.photobucket.com/albums/a59/moteel/100_2802Small.jpg
Photos are not the best, but you can see how it turned out. It is 18" radius. Ballested deck is built from 1/4" plywood and 1/8" hardboard. Bridge girders and hand rail are plastic. Bridge shoes and track are Micro Engineering.
Wow, that bridge is pretty cool. Nice job!
more more…
Great “art” Hill
Great “steel” bridge
steel
AMAZING bridge! You should sell the dsign to the Railroads [:)]