Grade Rise Limitations...Modeling Big Four Bridge


C

CSXfan75

Member
I have a layout plan involving The Big Four Bridge, this east-west line was built as the Bellefontaine and Indiana Railroad which ran from Galion, Ohio to Union City on the Ohio-Indiana border. It was built in conjunction with the Indianapolis and Bellefontaine Railroad thus providing a route from Cleveland and the East to Indianapolis, and later St. Louis. In 1864, the two were merged into the "Bee" Line: the Bellefontaine Railway, in 1869, into the first "Big Four": the Cleveland, Columbus, Cincinnati and Indianapolis Railway, and in 1889, into the second "Big Four": the Cleveland, Cincinnati, Chicago and St. Louis Railway. In the early 1920s, this railroad relocated its tracks from downtown Sidney to the south edge of the city over the then new Big Four concrete arch bridge. Early in the twentieth century, it was leased by the New York Central System. Later the Big Four was taken over by the Penn Central, then Conrail, and finally CSX Transportation. As you can see in the attached photos, its a long and high arch bridge still active with CSX and many others. It is very impressive to watch trains roll over it, almost scary as the bridge has aged significantly.
My question is in modeling this bridge on a shelf layout in N scale, what is the best grade percentage and height that would coinside with the rest of the layout. Mind you this is just a quick, basic draw-up, the track plan can and will be adjusted according to bridge specs. the layout will pretty much be built around the bridge, industry placement and other trackage is not permenant in this drawing. (but I do think its pretty cool for a green horn!!:cool: :D
 
I would try to keep the maximum grade down to 2%. Any steeper and you'll need either a lot of head end power or some helpers. A 2% grade will require 50" of run on both sides of the bridge so you have to look at your layout plan and see if you have that kind of room available.
 
Why don't you make an opening in the top of your shelf to build the bridge like I did on my layout & then the tracks will be level going to & from the top of the bridge.

Larry
 
Larry said:
Why don't you make an opening in the top of your shelf to build the bridge like I did on my layout & then the tracks will be level going to & from the top of the bridge.

Larry
Click to expand...

Im not sure I understand what you mean here, can you elaborate a little more here?
 
My bridge is scratchbuilt out of wood. It's 55 in.'s long & 28" high. It has 4 mainlines running on top. It's not finished just yet. About another 4 days of work on the plaster sides on the mountain slopes & adding the water scene at the bottom.

Larry
 
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UP2CSX said:
I would try to keep the maximum grade down to 2%. Any steeper and you'll need either a lot of head end power or some helpers. A 2% grade will require 50" of run on both sides of the bridge so you have to look at your layout plan and see if you have that kind of room available.
Click to expand...

Do you mean 50" (4' basically) on either end of the actual bridge platform? In other words, about 4' of rise from 0"--> bridge top, then another 4' decent from that to 0" on the other end?

My original "vision" was to set the actual bridge height at about 6" over the shelf surface, so at that height, what kind of track height would be best to make a rise? (forgive my lingo, im still learning!)
 
The top of my bridge is even w/the top of the train table. There's no riser. No incline or no hill to climb.

Larry
 
The formula for calculating the amount of run is Rise divided by the Gradient(%) = Run. In this case, the top of your bridge is 6" above level. In order to maintain a 2% grade, you need 300 inches of run on each side of the bridge. Yes, that's right, 25' worth of run on each side of the bridge. That means at least 50' feet of layout just for this bridge. That's probably not practical. Even if you go to a a 4% grade, which is very steep by mainline standards, you'd still need 12.5 feet on each side of the bridge, or a total of 25 feet, also probably not practical.

What Larry did is have the bridge be on level track but look like the kind of brdge you want by making a hole in the shelf and running the bridge across the hole. He'll then fill in the sides with plaster and scenery and add water to the river below. It will look like the trains are still corssig a big bridge but you have no grade to deal with.
 
You could alos build it up a little with risers and plaster to scale to give you the effect also !
 
That makes sense, but the bridge I want to model spans a good distance, im not sure what it would equal in N scale, but I bet every bit of 4'! When I get to the point of building the structure of the shelf, Ill see what I got to work with. Thanks for the info Jim, Ill definately use that formula somewhere Im sure, and I like the idea Larry has with the depression in the shelf, makes things simpler.

Zac
 
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