Yes I would use a piece of thin metal myself, but I believe there is only 4 inches of clearance required to clear autoracks and dbl stacks,...4 inches from top of rail on the bottom level, to the bottom of roadbed overhead??
Brian
My Layout Plan
Interesting new Plan Consideration
railandsail riogrande5761 The grades on the two stretches of track here are 2.9% each, one going up and one going down. I would have preferred gentler but I was able to pull 22 car trains ok with two six axle diesels. What sort of clearance did you achive in that overpass area? And what sort of horizontal distance,...approx??
riogrande5761 The grades on the two stretches of track here are 2.9% each, one going up and one going down. I would have preferred gentler but I was able to pull 22 car trains ok with two six axle diesels.
The grades on the two stretches of track here are 2.9% each, one going up and one going down. I would have preferred gentler but I was able to pull 22 car trains ok with two six axle diesels.
What sort of clearance did you achive in that overpass area? And what sort of horizontal distance,...approx??
Brian,
Where the top track passed over the bottom in the distance was just enough to clear my talled autorack and double stack cars. However, to achieve the clearance, I bought a metal strap piece at home depot that would support the track above with plenty of weight carrying capacity. I think the tallest piece of rolling stock would clear the bottom of the overpass with about 1/4-inch extra space.
I think the bridge over had a horizontal distance of about 9 or 10 inches from memory. That piece of metal I bought was enough to span that space with about an inch on each side for support.
I designed the no-lix so I could have a mild a grade as possible yet still get trains from the staging yard below up and over to the top level. There wasa bout 7 1/2 inches head room over the staging yard. Not a lot, but enough to reach over rolling stock on front to access trains to the back.
Rio Grande. The Action Road - Focus 1977-1983
I wanted to get some significant elevation changes on my layout as well. At the time I was concerned that people would think it looked toy-like. (I find most of my visitors actually don't care, however). I decided to hide the grade change in a tunnel. The train enters the tunnel at one elevation, about 18" later it exits at another elevation and continues to climb for a bit. Inside the tunnel there is just over 11% of grade. My little logging trains don't have a hard time with it and it allows my logging camp to be significantly higher than the rest of the layout.
Hope this helps...
On YouTube at It's My Railroad
The more you learn about creating workable track plans for the head-end power you have to work with (any one or combination of your locomotives), the more involved it actually gets. You need gauge loading clearances (measured sideways from your rails), overhead clearances (measured from the tops of the bottom rails), and vertical curves because a kink upward and downward by more than about 1% is likely to hang up trip pins, cow-catchers (properly called 'pilots'), or belly tanks on diesels. It's not enough just to want a grade for its own sake, or an overpass or crossing for the same reason.
You have to think of the power, or properly the 'tractive effort' at the rails, managing grades, grades with curves, grades with long loads trailing the power, or severe grades with any amount of power. The power is one thing, but also those darned clearances. As you agree to have a steeper grade, the vertical curve into and out of it needs to be longer and more gradual. The longer those curves are, the less length you have at a given steady grade to get the elevation you need at the top, or the clearance you need for an overpass. If you find you need a whopping 4% grade to get that height, you'll also need longer vertical curves to keep trip pins from snagging ahead of the locomotive, or driver wheels from getting light or even lifted right off the rails, thus impacting tractive effort. It's almost a conundrum. That is why those of us offering advice to beginners or to seasoned people who have never had a serious grade, that they have to keep more than just the height they want to achieve in mind. And, why we urge people to work assiduously to keep their grades as low as possible. Even curve-free if that can be done. Even, to abandon the idea once an important factor becomes a real problem that can't be managed without some serious compromise.
If it matters, I use a simple multipier of 5. In inches of vertical curve, I want five inches for every full percentage point of change in grade. For 3% grades, I need 15" of transition from, or back to, level. That's not very generous, and probably not what you'd see on the larger and more advanced layouts by some of the big guns in the hobby. Or, if it suits their purposes for the space they have, they might just agree with me.
hon30critterThe curve increases the amount of force required to pull the train up the grade, in effect making the grade steeper. There is a formula. Darned if I can find it.
The traditional rule-of-thumb for HO is 32/R, with R being the radius of the curve. This is added to the nominal grade to calculate the effective grade. So for a 2.5% nominal grade through a 24” radius curve, the added effective grade is 32/24 or 1.33%. This makes the total effective grade in this example 3.83%. There is some empirical testing of this formula being done that suggests that it may underestimate the effective additional grade in HO in curves below 24” radius. But that has yet to be completed.
For a transition from level to grade, I shoot for a longest car length for each percent nominal grade, but a little less will sometimes work if care is taken to make it very smooth. A level area of at least the longest car length is needed when moving from upgrade to downgrade (and vice versa, of course), even with grade transitions.
I also try to avoid any grade changes within or too near to a turnout (again, one longest car length is my goal)
kasskaboose1. Anything to consider in starting an incline a curve track vs. straight? I had elevated track on a curve and it was fine. 2. Does the trig equation of rise/run come into play in considering elevation? If so, how? Perhaps that you can't have an elevation w/o some type of flat area before a descend?
Grades may start on straight or curved track. No difference, except for the effective additional grade as noted above.
Rise divided by run to determine nominal grade percentage is basic math. But yes, that calculation does impact how high the track may climb. You need enough running length to achieve the elevation gain you want with a reasonable grade for the type of equipment, desired train length, etc. There’s no free lunch.
Byron
Layout Design GalleryLayout Design Special Interest Group
kasskaboose1. Anything to consider in starting an incline a curve track vs. straight? I had elevated track on a curve and it was fine.
The curve increases the amount of force required to pull the train up the grade, in effect making the grade steeper. There is a formula. Darned if I can find it.
kasskaboose2. Does the trig equation of rise/run come into play in considering elevation? If so, how? Perhaps that you can't have an elevation w/o some type of flat area before a descend?
Whenever you go from a flat track to a grade there has to be a vertical easement. The easement has to be long enough that the locomotive's trucks can still maintain contact with the track and long enough to prevent coupler trip pins from snagging the track.
Here is a formula that was posted in the March 1979 MR:
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Perhaps my questions can help cowboy (or anyone else) make decisions about grades:
1. Anything to consider in starting an incline a curve track vs. straight? I had elevated track on a curve and it was fine.
2. Does the trig equation of rise/run come into play in considering elevation? If so, how? Perhaps that you can't have an elevation w/o some type of flat area before a descend?
Thanks!
hon30critter SouthPenn Plus I have my rolling stock weighted at twice the normal weight. By 'normal' weight are you referring to the NMRA RP formula of one ounce plus 1/2 oz per inch? If so, why are your cars so heavy? I'm not questioning your decision. I'm just curious about the reasoning. Thanks, Dave
SouthPenn Plus I have my rolling stock weighted at twice the normal weight.
By 'normal' weight are you referring to the NMRA RP formula of one ounce plus 1/2 oz per inch? If so, why are your cars so heavy?
I'm not questioning your decision. I'm just curious about the reasoning.
Thanks,
Dave
I would like to have 50 or more cars in my trains, but that is not possible. Most of the overweight cars are coal cars. I had them weighted at NMRA recommended weight then I doubled the amount of weight I had added. This kinda-sorta makes the trains seem like I have 50 cars behind the engines. I also use a lot of imagination.
Since I started using RailPro engine control it is super easy to have three engines at the front of the train and two helpers in the middle.
SouthPennPlus I have my rolling stock weighted at twice the normal weight.
On my layout I have a 'helix' that move trains from one level to the other. The combination of grades and curves makes this a tough pull. Plus I have my rolling stock weighted at twice the normal weight. This requires multiple engines when I pull 28 cars. That's the maximum my return loops can handle. The grade is probably 2.0%+.
This looks like an arrangement I may employ to reach my stagging tracks.
BTW, some excellent contributions by Selector and Doctorwayne in their very recent postings.
I'm coming to the conclusion that 3% grade on non-helix grades, on our model railroads, is NOT so bad.
Here is a long (for my layout) coal train going down grade:
You're right, Brent, that the layout doesn't usually have to be at all the same level, but all of my benchwork is at the same height of 31", as I had to work from the lowest common denominator to allow sufficient clearance where the layout was planned to have two levels.I never had a trackplan - that was decided by the room's odd shape. What took considerable calculation was determining the height of the roadbed, in various places, which would keep all of it at grades no greater than 2.5%. Even the peninsula, which encompasses the 45' long grade to the second level, has benchwork only 31" above the floor. Almost all of the roadbed (and scenery and structures) is on risers...
There are five staging areas at four different levels, four of them seen here...
...with the fifth one at about the same height as the upper one in the photo above, but in another room.
Wayne
doctorwayne A 2.5% grade on its own doesn't look excessive, but, as is the case in the photo below, two 2.5% grades, in the opposite directions in the same scene do look steeper...
A 2.5% grade on its own doesn't look excessive, but, as is the case in the photo below, two 2.5% grades, in the opposite directions in the same scene do look steeper...
I have one of those as well.
Also, remember that all the benches don't need to be the same height as well. Some people don't think of that one.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
My around-the-room layout has grades everywhere, to accommodate multi-level staging and a partial second level. I tried to keep a 2.5% maximum grade, as most of the grades also involve curves, and this does affect train lengths. A 2.5% grade on its own doesn't look excessive, but, as is the case in the photo below, two 2.5% grades, in the opposite directions in the same scene do look steeper...
My hope is that once the apparently very slow-growing forest fills in, the effect will be mitigated. Even in the current landscape, it doesn't look as bad from a distance...
This area, to the right of the photo below, has the same situation, but is less noticeable because of the icehouse in the foreground (there's a track on a grade, rising towards the camera, right behind it) while the mainline, dropping down to meet it is also partially hidden by the icehouse....
Because of the aisle width here, a viewer can't see the grades well enough to notice the contrast, and for the same reason, it's difficult to show in a photo of it.
Here's an aerial view, with the mainline on the left dropping down to the turnout in the distance, while the curving secondary line climbs towards the same turnout.Beyond that turnout, the track rises, until levelling off in the next town....
In that town, the tracks split again, one going up towards the second level and the other down to the lower level of the layout, as shown in the earlier photos of the bridges.While I generally run fairly short trains, perhaps up to 16 cars or-so, most trains are doubleheaded, and for longer trains or heavier ones, they may get a pusher, too.
To me, a 3+% grade looks quite steep. Even so, I have to have one, on a broad curve, that only lasts about 4' on my main. This allows a much more gradual slope up to my overpass area, a twin-tracked truss bridge.
On my other completed layout, ten years ago, my mains grades ran in the order of 3.5%. I had trouble with a BLI 4-8-4 pulling more than 4 Walthers heavyweights and a couple of head-end reefers. So, I try to keep such grades to a minimum. However, in our confined spaces, if you want an overpass clearance, say for a GG1 and upraised pantograph, you need a minimum of 4.0", especially on curved aperture, stone type or cement, tunnel portals. Gaining my own minimum of 4.25" requires a run in the order of 141" with an average grade of only 3%. But, that's without including the height of the deck for the rails that are passing over, as well as the ties and rails if they sit on the bridge deck. For a very slim deck and tracks that support them, you'd still have to add over 1/2 of an inch of height that the rails have to gain over the tops of the rails below the overpass. Then, you have to factor the vertical curves at either end of the grade.
This all means that you're likely to need grades in excess of 3% on your typical layout. How badly do you want such an elevation change? Are you willing to shorten trains or to consist two or more locomotives to get the train up such a curved path?
I think the size and shape of the layout should determine what you can get away with from a visual appeal point of view. A guy asked me to come and see his room sized N scale layout with grades so steep only the loco's could get up the hill. He had spent a small fortune by going out and loading up on everything, only to be disappointed with what he had built. I swear some of his grades were 35%.
I have often told people, you can have ups and downs on a layout for no other reason than to be going up and down. You don't have to be going over something, although in this case you are going over the Rockies. All my grades are 2% or less and like you my layout is over the Rockies.
I agree with Sheldon about 3% being a maximum grade, I like long trains winding through my Rockies so I went up and down on grades I thought looked good. We work with what we have and compromise doing so.
Here is my up and over a long time ago.
floridaflyerA grade on a helix increases the effective % of grade a 4% grade in a helix would have an effective grade of about 5+% depending on the radius of the curve. There is a formula for this but I don't have it handy.
Grade equivalent, is the drag (expressed as a grade) that a train sees from going through a curve. There is an easy rule of thumb for HO. Basically 32/radius of the curve = grade equivalent.
By way of example, a train going through a LEVEL 24" radius curve will experience a drag equivalent to a 32/24 = 1.33 degree grade. So if a 24" radius helix produces an actual 2.65% grade (~2.5%) then the train will experience an almost 4% grade.
A grade on a helix increases the effective % of grade a 4% grade in a helix would have an effective grade of about 5+% depending on the radius of the curve. There is a formula for this but I don't have it handy. To your question though, a 4-5 % grade would look ok, especially if broken up by tunnels, sheds and whatnot.
Personally, I think 3% should be considered the max in most cases.
My preference is for 2% or less, but I like long trains. Even 2% requires a lot of power for my 30 to 50 car trains.
Sheldon
In model railroading 4% is fine, anything past that and you may or may not have issues. This is with like a 10 car train weighted normally. If you run heavier cars this number would be less and of course lighter more. Also of note is the length of the run effects the amount of cars more than the grade. If your grade is only 8 cars long then you can a longer train as the engine thinks it is only pulling 8 cars up the grade (now their are of course more dynamics that what I stated that will effect the amount of cars but I hate higher math so I won't go into formulas).
the soulthren rr had the saluda hill a 4.7% grade . it was so steep that there were two safety turnouts on it for down hill trains(read as runaway train) used massive amounts of power to get trains up the hill.
I am going to have a 5% grade on my next layout. It will be on an industrial branch. Tests have shown that a Walthers H10 switcher will pull four cars and a caboose up that grade.
.
I would never do that on a mainline.
-Kevin
Living the dream.
If you have steep grades you also need a transition at each end or you risk cars uncoupling as they enter or exit the grade.
Lackawanna Route of the Phoebe Snow
cowmanI would think that much of the appearance of the grade could have to do with the way you do the surrounding scenery.
Correct: I once built an NTRAK module that everyone looking at thought had a grade on the main lines (violation of standards). When properly leveled in a layout, the actual grade was 0.0%.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
Hi bigcreekcowboy:
In my opinion typical model railroad grades don't look steep enough! We are currently building a new layout at our club. Last week we installed some of the sloped track. We have a 2% grade. Quite frankly I'm disappointed with how it looks. After 20' of sloped track, we are only about 5" above the level track. I would like to see a greater separation between levels but the best we can do without resorting to a helix is about 11". We want to be able to run longer trains so unfortunately we do have to observe the laws of physics.