Hi all,
Working on my first layout with my son. We've built the benchwork and cut the plywood sub-roadbed. This weekend I'll probably finish the joists and risers for the subroadbed and mount it all down. I'll probably put up the backdrop as well, since it will be easier to get it up now than before everything is layed out.
I will have two bridges in my layout; one where the track goes over a road, one where a road goes over a sunken track.
For where the track goes over a road I was planning on using something like Walther's Plate Girder Bridge as this is the type of bridge in the town we're trying to model. It seems like, before I lay track, I should get the bridge, build it, and then cut the plywood subroadbed in order to put the bridge in place before I lay track. Is this true? Is there an easier way of doing this?
It seems if I do that, then I'd need to add bridge piers and any other scenery around the bridge. This seems premature since scenery is a long way off.
Where the road goes over the sunken track, I would need a bridge the width of the sunkaway (about five inches at that spot) or find a bridge and cut the sunkaway the width of the bridge.
Again, is there a better way? Is there something I haven't thought of, this being my first layout? I really haven't seen this addressed anywhere.
Also, since most bridge models I've seen seem to be a bit longer than I want, is there an easy way to shorten them? Assume I'm competent with cutting/gluing and other aspects of modeling. (even if that's an incorrect assumption...)
Thanks!
Jim
P.S.
I haven't shown this to anyone yet, but I've been documenting our build in a blog at http://coveringourtracks.wordpress.com/. There isn't a lot there yet, so forgive me.
Amateur father and son building our first layout: http://coveringourtracks.wordpress.com/
Other Forum users can give you more immediate answers and advice, but I just had to comment here because it struck me as a huge coincidence that I happen to be, at the moment, writing a section of an article for our March 2015 issue about how I built two such bridges on our N scale 2015 project layout. The rail bridge is a section of track, cork roadbed and all, under which I put a styrene floor and glued Atlas bridge girders to the sides, a simple construction. The road bridge is a bit more complex; I used cork roadbed to build a smooth approach over the foam hills on either side, scratchbuilt two pile trestles that I glued into place on either side of the track, built a framework out of styrene I-beams, and topped that with a scribed wood deck. Neither is as complicated as you seem to fear. Good luck with your bridges!
--Steven Otte, Model Railroader senior associate editorsotte@kalmbach.com
NOW!!!
You should add the bridges as soon a possible!
Or, at least place an accurate representation across the proposed span- -wood mock-up, cardboard, paper, etc.
The late, great, John Allen pioneered the concept of finishing the scenery before any track had been lain.
As far a bridges go the sooner you can place them the better. I’m not saying that you should make them permanent during the construction phase. If you have the finished bridge during construction you can adjust your track work to make the placement more functional.
I have one span on my pike and I’ve upgraded this bridge three times.
You can not only shrink the span of a bridge you can also expand it. More commonly referred to as kit bashing. The second bridge I built was bashed from three kits.
To do this you’ll need a few items: a good carpenter’s square (or two), a sharp hobby knife, a razor saw, an assortment of Styrene sheets, bonding agent and, most importantly- -a plan, diagram or photo that you want to replicate on your pike.
Good luck, please keep us informed on your progress and I hope this helps.
To all viewers- -Go to his blog and see what the OP is doing to further this hobby. Great stuff!!!
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
Steve hit the nail squarely.
IIRC, the Atlas deck girder is as long as one length of snap-track, 9 inches in HO. If modeled as a ballasted-deck bridge you can simply square up the edges of the cookie-cut roadbed where the road is going to be, then add the side girders (attached to the cut cookie) abutments and such when you do the scenery in that area.
The road bridge can wait until you are actually doing scenery work. If you're modeling a railroad that's been there for a while, your road bridge could be a stone arch - two tunnel portals spaced apart with thick foam plastic carved (inside) to look like assembled cut stone. Back in the 19th century they built things to last!
Chuck (Modeling Central Japan in September, 1964 - with LOTS of bridges)
Good answers so far. What I find most important is to lay the tracks over the area first, with the gap of an appropriate size in place. The idea is to make the grade constant there. You want to avoid hitches and gaps that might make the rolling stock lurch onto the bridge, over it, or off it. The best way is to join a full length of flex to ends about a foot or so back from each cut end of the roadbed. That way, it is seamless over the span. (If you need to have that bridge removable for some reason, then you'll need to gap the rails and rely on sliding joiners to keep power to the bridge rails...sometimes an iffy proposition.)
From there, with your bridge ready, you simply lift the bridge into place from below and prop it up with blocking so that the grade doesn't change. This takes some patience and care, but it's entirely doable. The bridge deck should just make contact with the ties and support the tracks to keep that important grade consistent.
Glue or tack the pedestals or abutment underparts in place, and then clad them with styrene or plaster elements to look like concrete or strone abutments, or clad them with stained stripwood if they are going to be cribbed.
I always build, or apply, my scenery materials, including hot gluing aluminum window screen if that will be the base of my ground goop scenery there, AFTER I have the bridge and abutments looking like they were properly engineered and installed. Build up the terrain and vegetation around that place after all that bridge and abutment construction.
-Crandell
I planned my bridge to be a tandem truss bridge & girder bridge combo. I wanted to get the layout built and running before assembling them and adding permanent abutments & middle pier. Determining the total length to be a bit less than a 36" flex track, I cut the plywood subroadbed ends of the future bridge gap a bit narrow (so it could be fine tuned later when I had the bridges built). Then added temporary abutments and a middle pier, spanning the temporary gap with a piece of yardstick cut to fit. Temporarily added a needed length of flextrack that I fit into the adjoining tracks. Then I could run trains and check things out.
The bridges I used (Central Valley) require adding the rail. I made them a long, single unit, removing the rail from the temporary flextrack and using it as the bridge unit rails. Of course it was the right length to fit into adjoining gap since that was where it was removed (I had to slide the right number of ties to each end). I had to get the plywood approaches trimmed to the right exact dimensions for the bridge abutments and get the abutment heights just right at two points; i.e., the tie bottoms relative to the adjacent roadbed & the ties over the abutment, plus the abutment shelf relative to the bridge shoes. All this could be done at once if the bridge was built prior to running. I used Chooch abutments and pier, cut shorter on my bandsaw to get overall height needed, and slightly adjusting the depth needed between roadbed height and bridge shoe height as needed by minor dremeling or shimming as needed at the shoe spots. A bit of trial and error was needed.
Note that I did not want the bridge rails to end just above the transition from bridge to adjacent areas as I wanted to avoid stacked transitions (subroadbed, roadbed and rails. If adding your own rails, it's nice to extend them past the bridge somewhat so the rail gaps occur over super-flat roadbed. I did have one bump above one abutment so had to remove some things and do a bit of dremel fiddling to the abutment to flatten things out (even with the solid rail above that point).
Not a "best" way to do things, but that's what I did and perhaps some of my insights will be of use in your situation.
This is the temporary setup, with the bridge flex removed and the rail installed on the combo bridge (not seen, ready to install).
Here's some shots after the bridge unit was installed.
Paul
Modeling HO with a transition era UP bent
The bridge is probably going to be structural and support the tracks. It would probably be the best idea to complete it when you complete your road bed. I would suggest making the abutments out of plaster or patch/bolt concrete (something that is really fine). You can make the abutments structural, and work the scenery around them. Remember that on the prototype, the land is shaped somewhat around the bridges when the project is complete.
You go for the bridge after the dentist pulls out your teeth!
Here is elevated structure of LION under construction. It is upside down on what was then an open stretch of railroad table. In the middle of this, you will see a bridge that will carry the elevated across 125th Street, but wait, that is not all, what it really is is a splice between the two sections of the el. On the bottom a metal plate is glued to the boards, and top and bottom is some wood material that is screwed in place to provide rigidity to the joint.
You can see that bridge on the finished railroad more than halfway down the elevated line.
Here is a similar bridge on the IRT subway.
Here is bridge of LION across the Gowanus Canal. It is a four track mane lion, the Atlas spans support the two outer tracks, the middle tracks are supported by a piece of masonite. There will be bridge members built into a superstructure so that it will look like the one single bridge that it is supposed to be.
Here is same bridge in NYC as seen from a canoe. The railroad bridge has four story buildings under it, the brigde is actually in the station, but there are additional spans that take the railroad over existing buildings. The drwa bridge is entirely under the railroad bridge and lifts the road out of the way of barge traffic. The BQE passes over the canal on a highway bridge in the distance.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
I add my bridges when I am doing the scenery work. Before then, I use some temporary ones made of wood planks. Here is a place on my layout where I have three bridges. I use the planks so I can run trains while continuing to work on the layout. The track is attached to the planks, but there are rail joiners on the track at both ends so they can be lifted out and replaced by the model bridges when I am ready for them.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
There is always going to be many roads to the same similar result kinda like all roads lead to Rome. I've tried many many ways and for my self I found it best to do the risers and install the roadbed , raise the roadbed to the height you want and keep in mind this can change as you may want to have track higher or lower depending on any given scene and you can't adjust 4 feet of risers without effecting the rest of the layout risers , it all has to work in unison. Then lay the track and run many many test on the rails with different locos in each direction , make sure you have enough drop feeders if your dcc. Once the rail elevations are for certain figure out if the ground work allowable area will be good for any bridges, check for clearances with the guage, figure out where the track will be the easiest to manipulate for a bridge to have a straight track, figure out if you plan on having the bridge held up by abutments or if it will be sitting on the wood roadbed itself and the abutments built up afterward as a scenic effect. Cut the track length first making it an inch or more longer than each end of bridge to be used and remove track piece, now you can cut the road bed and try the bridge in place and lay the cut out rail back in place. You also have to keep in mind that the roadbed has to have enough supports to keep the area of bridge supported and or moved. Hope this helps.
Lynn
Present Layout progress
http://cs.trains.com/mrr/f/11/p/290127/3372174.aspx#3372174
selector Good answers so far. What I find most important is to lay the tracks over the area first, with the gap of an appropriate size in place. The idea is to make the grade constant there. You want to avoid hitches and gaps that might make the rolling stock lurch onto the bridge, over it, or off it. The best way is to join a full length of flex to ends about a foot or so back from each cut end of the roadbed. That way, it is seamless over the span. (If you need to have that bridge removable for some reason, then you'll need to gap the rails and rely on sliding joiners to keep power to the bridge rails...sometimes an iffy proposition.) From there, with your bridge ready, you simply lift the bridge into place from below and prop it up with blocking so that the grade doesn't change. This takes some patience and care, but it's entirely doable. The bridge deck should just make contact with the ties and support the tracks to keep that important grade consistent. Glue or tack the pedestals or abutment underparts in place, and then clad them with styrene or plaster elements to look like concrete or strone abutments, or clad them with stained stripwood if they are going to be cribbed. I always build, or apply, my scenery materials, including hot gluing aluminum window screen if that will be the base of my ground goop scenery there, AFTER I have the bridge and abutments looking like they were properly engineered and installed. Build up the terrain and vegetation around that place after all that bridge and abutment construction. -Crandell
Hi Crandell, I've used ground goop in the past for adding texture before I built up the terrain, can you give some instances of where you used the ground goop?
I agree, add the bridges as you are laying the track., In my opinion the preciseness of the fit between the bridge track and adjoining track dictate that the process be done this way. Of course you will need to make the bridge removable, so you can complete the scenery under the bridge easier. For this reason doing the scenery under the bridge is probably the first scenery I will complete, after the rest of the track work is completed.
NP 2626 "Northern Pacific, really terrific"
Northern Pacific Railway Historical Association: http://www.nprha.org/
Jim,
All good advice you have received. Another trick you might be able to get away with depending on your application is to just cut the sides off the plate girder bridge and glue them to both sides of your sub-roadbed. This will eliminate risk factors for grade/camber changes etc. Of course if you need to do scenery work under the "bridge", this might create an issue, so think about it.
Tim
wickman selector Good answers so far. What I find most important is to lay the tracks over the area first, with the gap of an appropriate size in place. The idea is to make the grade constant there. You want to avoid hitches and gaps that might make the rolling stock lurch onto the bridge, over it, or off it. The best way is to join a full length of flex to ends about a foot or so back from each cut end of the roadbed. That way, it is seamless over the span. (If you need to have that bridge removable for some reason, then you'll need to gap the rails and rely on sliding joiners to keep power to the bridge rails...sometimes an iffy proposition.) From there, with your bridge ready, you simply lift the bridge into place from below and prop it up with blocking so that the grade doesn't change. This takes some patience and care, but it's entirely doable. The bridge deck should just make contact with the ties and support the tracks to keep that important grade consistent. Glue or tack the pedestals or abutment underparts in place, and then clad them with styrene or plaster elements to look like concrete or strone abutments, or clad them with stained stripwood if they are going to be cribbed. I always build, or apply, my scenery materials, including hot gluing aluminum window screen if that will be the base of my ground goop scenery there, AFTER I have the bridge and abutments looking like they were properly engineered and installed. Build up the terrain and vegetation around that place after all that bridge and abutment construction. -Crandell Hi Crandell, I've used ground goop in the past for adding texture before I built up the terrain, can you give some instances of where you used the ground goop?
Lynn, I have used the formula provided in this forum by Joe Fugate before he left to run his own forum and ezine business. I have used it on two layouts, the one I abandoned three years ago and the new one that is slowly being completed.
I built a timber trestle from scratch on the last layout, and used splined roadbed. I cut the roadbed and removed a chunk about 13" long. I then built the trestle to fit the gap, but kept the bent frames rather long so that I could trim them. I built timber and gravel abutments over which I lay the ends of the stringers making up the deck of the trestle. I had to match the deck (stringers) to the spline roadbed meeting it on either end of the trestle, so when I had them at the same height, I just built the abutments to support it. That left the trestle suspended between the span, and from there I just made the aluminum base and spread ground goop under the bent frames. I also spread the goop around the abutments, and then covered it all with maybe three types of ground foam from Woodland Scenics.
Overhead view:
Here is a view from across the open pit style layout looking across to the trestle in the far corner. Note that all the terrain on this layout was aluminium window screen and group goop layered over it.
I like to get the supporting structure(s) for a bridge built as soon as possible after getting the basic roadbed in place.
Here you can see two bridges cut into the roadbed, with support for the abutments so the bridges can be temporarily installed and trains operated.
I usually remove bridges while building scenery to protect them from the mess. Here I've temporarily re-installed one after cutting through the scenery shell to get the abutments back in. The track mounted to the bridge comes out with it, and is easily connected back to the rest of the track by sliding joiners in place. I don't permanently solder the joiners until I'm nearly done with scenery.
This bridge is permanently installed. The abutments are glued in, gaps filled with finished scenery material, and so on. Trains were running through this area for years before everything was glued in.
Rob Spangler
selector wickman selector Good answers so far. What I find most important is to lay the tracks over the area first, with the gap of an appropriate size in place. The idea is to make the grade constant there. You want to avoid hitches and gaps that might make the rolling stock lurch onto the bridge, over it, or off it. The best way is to join a full length of flex to ends about a foot or so back from each cut end of the roadbed. That way, it is seamless over the span. (If you need to have that bridge removable for some reason, then you'll need to gap the rails and rely on sliding joiners to keep power to the bridge rails...sometimes an iffy proposition.) From there, with your bridge ready, you simply lift the bridge into place from below and prop it up with blocking so that the grade doesn't change. This takes some patience and care, but it's entirely doable. The bridge deck should just make contact with the ties and support the tracks to keep that important grade consistent. Glue or tack the pedestals or abutment underparts in place, and then clad them with styrene or plaster elements to look like concrete or strone abutments, or clad them with stained stripwood if they are going to be cribbed. I always build, or apply, my scenery materials, including hot gluing aluminum window screen if that will be the base of my ground goop scenery there, AFTER I have the bridge and abutments looking like they were properly engineered and installed. Build up the terrain and vegetation around that place after all that bridge and abutment construction. -Crandell Hi Crandell, I've used ground goop in the past for adding texture before I built up the terrain, can you give some instances of where you used the ground goop? Lynn, I have used the formula provided in this forum by Joe Fugate before he left to run his own forum and ezine business. I have used it on two layouts, the one I abandoned three years ago and the new one that is slowly being completed. I built a timber trestle from scratch on the last layout, and used splined roadbed. I cut the roadbed and removed a chunk about 13" long. I then built the trestle to fit the gap, but kept the bent frames rather long so that I could trim them. I built timber and gravel abutments over which I lay the ends of the stringers making up the deck of the trestle. I had to match the deck (stringers) to the spline roadbed meeting it on either end of the trestle, so when I had them at the same height, I just built the abutments to support it. That left the trestle suspended between the span, and from there I just made the aluminum base and spread ground goop under the bent frames. I also spread the goop around the abutments, and then covered it all with maybe three types of ground foam from Woodland Scenics. Overhead view: Here is a view from across the open pit style layout looking across to the trestle in the far corner. Note that all the terrain on this layout was aluminium window screen and group goop layered over it. -Crandell
Crandell that is a rather good example using the ground goop. Never thought of applying it right on window screen. I think I can see the ground goop showing through here and there?Do you apply rock castings into the ground goop when its fresh? I find that works really well.
Yours looks great.
Lynn, I just ladle it into place over the screen, and if necessary, tap it down a bit for an initial shaping. I find the goop wants to set up, or firm up, within seconds after I have placed it on the screen, so I literally have to spread and tap or jiggle right away. I walk away for a full day after that.
When I want to carve a rock face, I take a steel spatula and nick and scribe it. Later I will paint it with acrylic craft paints.
Thanks for your compliment.
I like to include the bridge with the initial trackwork, but I don't usually fasten it solidly in place until the scenery beneath it is complete. My layout base is pink foam and I use WS foam roadbed, so I can hold track in place with U-pins made by opening up paper clips. By doing this, I can have the track in place and run trains while I slowly craft the scene around the bridge. This is a Central Valley truss bridge. The deck portion bears all the weight in the kit. I built that first so I could use it to figure out how the scenery below it should be done.
Next, I cut into the foam to make the river bed. With the base of the bridge already built and the approaches available on both sides, I could both test-fit the bridge and run trains over it to check the trackwork and electrical connections.
The scenery work took place over a couple of months, while I was also adding more benchwork to the far side and putting in a long 4-track staging yard and a single through track. By having the bridge in place, I was able to test the trackwork all the way through. Meanwhile, I add layers of scenic material, from foam to plaster cloth to Gypsolite and rock castings. The superstructure of the bridge took some work, too.
I just finished the final scenic steps this weekend: ground foam and turf, Envirotex for the stream, static grass, trees and a moose. The first picture in this group was posted on August 10th, and the last on October 25th. The bridge was under construction before that, and I've still got to ballast the approach tracks, so this was about a 3-month project, working on-and-off while doing the staging yard. I'm not retired yet, either!
It takes an iron man to play with a toy iron horse.
selector Lynn, I just ladle it into place over the screen, and if necessary, tap it down a bit for an initial shaping. I find the goop wants to set up, or firm up, within seconds after I have placed it on the screen, so I literally have to spread and tap or jiggle right away. I walk away for a full day after that. When I want to carve a rock face, I take a steel spatula and nick and scribe it. Later I will paint it with acrylic craft paints. Thanks for your compliment. -Crandell
Thanks Crandell, great tip.
Thanks, everyone.
It looks like some of these bridges are more elaborate than what I'm going to use.
I ordered a 72' plate girder bridge from Walthers. My plan, after reading the advice in this thread, is to cut my roadbed so the bridge can fit, put a temporary bridge and support in place when I lay my track, build/paint the bridge, put the bridge in place with supports on either end, add "realistic" supports when I do the rest of my scenery. Sound good?
The one question I have, it sounds like the bridge I ordered (https://www.walthers.com/exec/productinfo/210-1903) has ties built-in. Do I have to strip the ties off one of my peices of rail and put the rail in place in the bridge's ties? Or can I just not use the ties supplied with the bridge and put my track right accross the bridge? Again, this is all new to me so I'm not sure how it's usually done.
That's the same bridge we're talking about in this thread:
http://cs.trains.com/mrr/f/11/t/239416.aspx
From that thread, I think the bridge's ties are similar to the ones on their truss bridge that I've just finished up. I took a 3-foot section of Atlas flex track and just removed the ties in the middle. Then I glued them to the bridge's ties with CA, after masking and painting the ties but leaving the strip where the rails attach unpainted. This gave me a continuous section of track that extends well beyond the ends of the bridge, so I avoided any problem with kinks in the track where it crossed.
jmerulloMy plan, after reading the advice in this thread, is to cut my roadbed so the bridge can fit, put a temporary bridge and support in place when I lay my track, build/paint the bridge, put the bridge in place with supports on either end, add "realistic" supports when I do the rest of my scenery. Sound good?
Yup. That should work.
Do I have to strip the ties off one of my peices of rail and put the rail in place in the bridge's ties? Or can I just not use the ties supplied with the bridge and put my track right accross the bridge?
I'd recommend using the ties that come with the bridge. They will look and fit better than the ties from your flex track. You can leave the flex track ties in place until you're ready to put the bridge in, then cut them out and slip the bridge, with its ties, in place under the rail. It shouldn't be tough to do at all.