OK, I’ll admit it! Turnouts on bridges aren’t exactly prototypical. None the less, it would be convenient for my club’s new layout to have a turnout which is about 50% on a bridge. How do we build the bridge?
I’m thinking about a scratchbuild using deck girders where the girders are not parallel in the area where the turnout has to be. Is that totally bogus, or is it a reasonable stretch of the imagination?
Thanks,
Dave
First, turnouts on bridges are prototypical. If you search on other forums you find lots of examples.
Here is CP’s Campden Place Bridge in Minnesota on Google Maps:
https://www.google.com/maps/@45.0293605,-93.2826374,239m/data=!3m1!1e3
And here are photos: http://bridgehunter.com/mn/hennepin/camden-place-rail/
I think there are two ways to design the deck bridge.
-Put one girder paralell to the main track and put the second girder at an angle from support to support so the diverting track can be accommodated.
I’d prefer the first one as it is less complicated to construct.
Here is another example, the BNSF Celilo bridge crossing the Columbia River.
From Google Maps: https://www.google.com/maps/search/bnsf+wishram+columbia+river+railroad+bridge/@45.651544,-120.9831996,473m/data=!3m1!1e3
http://www.somewherewest.com/gorge/BNSF4948EBWishram.jpg
Hopefully that helps a bit.
Regards, Volker
there’s an bridge with a turnout in Harper’s Ferry, WV
You could always use a concrete deck bridge or an arch bridge to get around the complicated steel structure work. That is what railroads do
The OP mentioned that the switch is 50% on the bridge, does that mean the switch in the middle of the birdge, or coming off the bridge at one end?
Here is a good thread displaying an (HO I believe) built switch, representing the famous Keddie Wye! It’s amazing how he did, and 12 years ago!!![wow]
http://cs.trains.com/mrr/f/88/t/71521.aspx
Maybe that thread can help with the building process, if you want pictures of the real Keddie Wye, it is in the Feather River canyon, EX Western Pacific, now UP.
Just here to share my [2c].
~Eastrail
Edit: my 20th post here. [wow]
Also, what is the length of the bridge?
Oil City, Pa
Cool photo!
Here’s another bridge in Pa. with the remains of a switch on it:
It’s now the Norfolk Southern, but once this was a Reading Co. bridge the Lehigh Valley used to access Allentown Yard after the Central of New Jersey quit running in Pa.
Originally, the Reading line continued across the LV main at the bottom of the map.
The switch was installed in the mid-'60s, I believe, when LV and CNJ started sharing track in Pa.
You’ll find photos of it in Mike Bednar’s Lehigh Valley Railroad: The New York Division.
Eric
There is a prototype for just about anything we can imagine, but a switch on a bridge may not be the best thing to do if there is another option available.
My point is that you need to be able to securely operate the switch. Obviously, a swith motor will be out of question, but maybe a miniature servo-motor small enough to be concealed by the bridge structure could do the job. A switch stand might be too big, as well.
Just thoughts…
There is just one handicap. The Keddie Wye doesn’t have turnouts on the bridges:
https://i.ytimg.com/vi/k3kqphgqSmo/maxresdefault.jpg
Regard, Volker
You don’t have to look very long for these prototypes.
And then there are these bridges: http://model-railroad-hobbyist.com/sites/model-railroad-hobbyist.com/files/resize/users/TwinStar/zephyr_triple-underpass_1950_portal(1)-800x557.jpg
You are right a small servo seems to be best for controlling the turnout. Or you use an Atlas Code 83 turnout with the according Atlas switch machine. Not easily camouflaged on not ballasted bridge.
Regards, Volker
Just another thought - switches are a potential risk for derailments, not only in our small world, but for the 1 to 1 guys as well. A derailment on a bridge is bound to end in a tragedy.
I hope that the switch rod end of this turnout is off the bridge and clears the abutment. Will be a problem with a sw machine, and some elaborite method of links to throw points will have to be figured. A ballasted deck would be the easiest and better choice for doing this, but if open deck, the supporting cross beams or bridge ties can be changed to suit the footprint of the turnout. As you say, modifications and replacing girder may also be needed.
I don’t believe the OP said which part of the switch was on the bridge(?) If the moving parts (points) are off the bridge, it would make things a lot easier. They’d just need to use a double-track bridge. If it’s a single-track bridge / track that splits into two at one end of the bridge, that would be more difficult.
I wonder if it’s the latter situation, a real railroad wouldn’t put the switch off one side of the bridge, and then use a gauntlet track so both lines cross the bridge (basically a single-track width bridge), then splitting on the other side.
I think it’s all very do-able Dave, If it were me, the turnout would be hand controled, with something that keeps a positive force against the points, to keep it all in place, maybe even the spring idea, with the boomerang looking bronze wire, I think Richotrains and a couple of others have shown what it’s about.
The structure could be built using deck girder parts, that you mention.
Mike.
Here’s another view of the LV/Reading Co. bridge at Bethlehem.
The track no longer connected led over to Bethlehem Union Station. If you go slightly south and to the east they have named the road Union Station Road, and there is an industry there with solar panels on the roof, which sits about right where the station used to be. BTW that industry does repairs and pressure testing on tanks - both road trucks and railroad tank cars.
Perhaps even more interesting, on the overhead view there you can see a through truss bridge for the road going over the tracks. When the railroad station was still there, there was actually a turn right in the middle of that bridge for a ramp that led down to the station parking lot. Yup, a T intersection in the middle of a road bridge! I vaguely remember seeing it before they tore it all down - trains were long gone from the station.
That line also linked back to Reading’s Saucon Yard. If you move diagonally the way the track appears that it woould have gone, you cna see evidence of the former right of way. Very evident in the block southwest of 3rd and
Thanks for all the pictures guys!! You have answered my question very nicely.
When I said “not prototypical” i really should have said “not common”.
Anyhow, to answer the question about what part of the turnout is on the bridge, it is the point end. The mainline actually follows the curved route (OK, slap my hand!) and the straight track just leads onto a short spur.
I hadn’t thought about how to throw it, either manually or with a motor. Throwing it manually would be fine because it is only a spur track and the operator will (hopefully) be right there if they are going on to the siding.
We also have the option of leaving out the turnout and just using the modelling space for something like a town scene or a farm scene.
Dave
What kind of bridge is it? Does it have plate girders extending below the roadbed level? A servo on its side is very thin. Or a bell crank, with a pushrood then going under the bridge deck to a location under the scenery beyond the bridge to locate a switch motor. The Tortoise remote mount is a bulky version of what I am thinking here - using RC parts you can make the same style of mechanism but very thin and potentially hidden beneath the bridge deck unless someone sticks their head way into the scene and looks up under the bridge.
–Randy
Hi Randy,
That is absolutely up in the air right now. Pardon the sick pun - up in the air - bridge - sorry, I couldn’t resist.[:o)]
We can pretty much build any type of bridge that we want, but a modified plate girder bridge with the turnout on top would seem to make the most sense for precisely the reasons that you suggest.
I have a bunch of small servos so that is definitely one possibility. I also think that a remotely mounted Tortoise could be used. I don’t think that figuring out the linkage would be too difficult, and since we are using Tortii everywhere else (I have always wanted an excuse to use that word![swg][(-D][(-D]), keeping things the same instead of creating one oddball arrangement would seem to make sense.
Dave
No, should be pretty simple linkage. FOr the final stange, to the turnout - think an arm, pivoted in the center. On one end, you have a piece of wire perpendicular to the arm. This goes up to the turnout throwbar. On the other arm, you have a piece of wire parallel to the arm, parallel with the ties of the track above. move this back and forth and the vertical wire moves side to side, moving the throwbar. Now one more arm near the edge of the bridge, this one not a straight arm but a 90 degree bent one. One actuating wire parallel with the bridge pushes and pulls on one arm, this makes the other side of the arm move back and forth across the width of the bridge - connect the wire from the other arm there. Sp now you push and pull the wire leading along the bridge to the scenery, this pushes and pulsl a wire that moves side to side relative to the track, with pushes and pulls an arm that on the opposite side has a wire sticking up through the throwbar.
Clear as mud? The wire leading under the scenery then connects to the moving part of a tortoise mounted on its side so that it pushes and pulls the wire.
You’d want to build the bridge and this mechanism before setting the bridge in place on the layout.
Now, here’s why I like servos so much (in addition to the lower cost). A simple 9G servo, with an arm attached, on its side, glued right to the roadbed under the bridge, with a wire sticking up through a hole to the throwbar. That’s it. Self contained in the bridge.
–Randy
