# Bridges on an incline, your opinions



## pat_smith1969 (Aug 21, 2016)

So I have a 5% grade and I need to put a bridge smack dab in the middle of it. I have looked at different types of bridges and like something like a truss bridge. Either that or something like an arch bridge

But since it will be at a fairly good grade, I think the supports might look off. The supports that are supposed to be verticle will be at an angle and that might look funny.,

Do I need to go to some type of flat deck bridge for my incline?


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## Magic (Jan 28, 2014)

On a 5% grade I would go with a trestle rather than a bridge.
That way the bents would be vertical but at different heights for the grade.

Maybe some of the Grand Central Gems wooden bents and a deck.
Of course you would have to custom build it but from the looks of your 
layout that should be no problem for you.


Magic


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## Lehigh74 (Sep 25, 2015)

For a 5% grade, I think a truss, girder or arch would look fine. Here are a few shots of each on a roughly 3% grade. I replaced the two Lionel truss bridges, not because I didn’t like their look, but because they blocked the view of the track behind them.


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## Chip (Feb 11, 2016)

How do you "reach" this 5% grade? A "slam" from "zero" to 5% all in one go or is it a more gradual increase to 5%? I'm looking at trying to add a 4% grade to my layout and people are warning me it "cannot be done"!


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## CTValleyRR (Jul 26, 2014)

"If you can dream a thing, then you can do it" -- Walt Disney

It's not that it can't be done, but that there are a bunch of operational difficulties that go with it. We normally advise newbies to steer clear of extreme grades because they go into it blindly and get frustrated by the complications. If you do it deliberately, with full knowledge of the issues and have a plan for mitigating them, then go right ahead and do it.

The "slam" approach is what causes the problems. People usually adopt extreme grades because of space limits, and the gradual, or "eased" approach requires more space. The grade itself may cause problems with what locos can pull up it, but the transition can cause coupler pins to dig in at the bottom and derailments at the top, and both ends can cause unwanted uncoupling. Gradually moving into a grade will mitigate the problems.

Two approaches are generally used. One is to build short segments (slightly longer than the longest piece of equipment that will use them) of gradually increasing/decreasing grade, usually in 1% increments. Using WS incline starters is an easy way to do this.

The second method involves using a long piece of flex track and allowing it to sag into a natural curve between the level track and the grade. This is a more elegant solution, but somewhat trickier to implement.

As far as the bridge question goes, the bridge itself can be on a slope, but trestles or piers should be vertical.

And always remember: your layout, your rules.


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## Chip (Feb 11, 2016)

Thank you most kindly, I have no intention of "highjacking" the thread but it seemed a good opening for the question in question. I have 2-3 and 4% riser starters and will be "easing" into and out of my most severe grades. I've got plenty of room and for some reason the 1% starter ramps were unobtainable but a 2% grade change should not cause me too much trouble, I'm a "pin cutter" so no drag there, just coupling I will have to watch closely.


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## pat_smith1969 (Aug 21, 2016)

Hey Chip
I totally don't mind you thread hijacking any thread I create... it is all good.

At the top of my helix (going up) I have a level portion, then I do actually kind of slam into my 5% grade.. but I did an easement at that transition. I took a belt sander to the plywood to even it out a bit... then I took a Orbital sander to the corkroadbed to even it out more... then the flex track went on top of it. I made sure the flex track didn't look like it had air under it. After the easements I have not had any problems at that spot in the track.

ON the other end I went from the wooden 5% grade, to a WS foam 3% grade, to a WS 2% grade. I have issues at that end but not because of the grade changes. Once again I took a sander to the cork roadbed to even out the transition. In someplaces I used drywall plaster to kind of fill in the transitions when they made a kind of cup area.

I am by no means an expert of course.


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## pat_smith1969 (Aug 21, 2016)

I will say that my steam locos have a hard time going up my 5% grade with more than 5 cars attached. My diesel locos have much less issues but at some point even they have a problem with a bunch of car attached.. luckily I only own a few cars and my layout is small enough where I cannot do more than 10 or so cars before it starts to look kind of ridiculous. 

Of course if I use cars with metal wheels I can pull more cars, I have a few real cheap cars with plastic wheels that can actually hold 5 cars on a 5% grade without rolling down the grade... those wheels are on my list to replace of course.


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## Chip (Feb 11, 2016)

pat_smith1969 said:


> I will say that my steam locos have a hard time going up my 5% grade with more than 5 cars attached. My diesel locos have much less issues but at some point even they have a problem with a bunch of car attached.. luckily I only own a few cars and my layout is small enough where I cannot do more than 10 or so cars before it starts to look kind of ridiculous.
> 
> Of course if I use cars with metal wheels I can pull more cars, I have a few real cheap cars with plastic wheels that can actually hold 5 cars on a 5% grade without rolling down the grade... those wheels are on my list to replace of course.


EXCELLENT! LMAO! "STUCK" on a 5% grade! I yousta "poo-poo" the difference between metal and plastic UNTILL the first time I unboxed a car with metal wheels and it SHOT down the track with a gentle push I was HOOKED and NO plastic wheels were henceforth "allowed" on my rails! Even really SWEET Loco's I was "pining" for were put off the purchase list until I had enough metal to "shoe" the entire fleet!


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## mesenteria (Oct 29, 2015)

I am a bit late to this topic. If 5% is absolutely necessary, it's what you have to build. It's _extremely_ steep. If you can find a way to reduce it, say by making an overpass' lower track dip further, that would be ideal.

Apart from that, and yes you will have to build in a vertical curvature to ease into the grade and then out of the top of the grade...which has the effect of eating into your space and forces your grade-proper to be that much steeper...*almost every bridge is on a grade*. There's virtually no level track anywhere. It may only be 0.1%, but bridges are usually AT GRADE and meant to bridge obstacles, not to interfere with the line's run to a summit by falling off grade, crossing the near-level bridge, and then restoring the grade again. It's unnecessary, and would just add to costs. The type of bridge is dictated solely by engineering and costs, including clearances overhead or below them, and the type of support that can be fashioned for them. If you have concrete abutments, and wide open clearances, you can have any type of girder or truss, depending on the intended load, quality of steel, sizes and type of timbers, and the spans needing to be crossed between pylons or abutments.


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## Chip (Feb 11, 2016)

This bridge was used to "even" out the top of the grade and by default became the entry point for my "river".


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## pat_smith1969 (Aug 21, 2016)

That actually looks pretty good on the incline. I thought it might look odd on an incline with all the vertical supports not being quite vertical. I am leaning towards building some Bents and doing a scratch built bridge, they look pretty awesome.


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## bluenavigator (Aug 30, 2015)

There are many bridges to chose. For long straight bridge on incline, I think this one is the right one to chose.








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I am thinking about which type of bridge to build over the river. I have 4 bridges to consider on my layout.


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