"N" Scale Grade


RxROtto

RxROtto

New Member
As I have said in other posts here that I am going to be working on a N scale track layout.
I have decided to have a grade on my layout. I have read several posts and if I am understanding correctly that my grading should be no more that 2 inches per 4 foot. Now the grade will be on a curve. Should my grading be longer since It will be curving upwards? Also once I reach the top of my grade how many feet does it have to remain flat until I can start the train on it's downward decent?

Thanks,
RxROtto
 
Ideally (and prototypically) a grade of 2% is what you should try for........the grade you are proposing is about 4%. A lot of N scale engines will struggle with a 4% grade....some will handle it. You can do a 4%, you just need to be aware you are creating a "problem" that can only be solved be limiting what you run. And as you noted, 4% with a curve will be an issue....even 2% with a curve can be an issue. As long as the transition isn't too abrupt, there isn't a fixed distance you need to wait before starting back down, although things can sometimes get interesting if half your train is going downhill at the same time the other half is going uphill.
 
I have three Athearn F45s that I've had pull 15 odd cars up a grade of nearly 6% without issue, but A. they're big engines, and B. they're cowl bodies. The two combined means that Athearn was able to cram a whooooole lotta weight into them. A single one of them pulls what my GP30M + SD45 can barely get moving! :eek: This means I could put steep grades all over my layout without a care in the world, as long as I don't mind benching all my other trains.

As Dave said, 2% is considered quite steep for the prototype. Not everyone has miles and miles of track of course so for the average modeller that may not be feasible if you want to have a scenic mountain route or a tall bridge. The rivet counters may scoff but I think anything up to 4% is quite doable, just don't expect to be hauling 30 cars up there in a lone engine. My current layout plan has one route peaking at about 3.5% and another at a much milder 2%, but both of these will be serviced by MU consists.

For the transition from a grade to level ground, flex track is your friend. With very little coaxing it flexes vertically as well! Keep in mind when you make the transition that doing it too sharply will cause problems for 6 axle diesels and all but the shortest steam trains. A pictoral example if I may-

grade.png


It's slightly exaggerated but you can see the problem a train with a series of rigid axles will face if you aren't careful.
 
I had to fight the same issue you are having. I set up the layout with about a 3% grade and the locomotives ran great but after attempting to add rolling stock I found that the locos could only pull three cars up the grade. As TrinityJayOne mentioned at the top of the grade I had an issue that the drop off was too fast and the wheels lost powere. One thing finally halped me, Woodland Scenics Sub-terrain system slopes. When I used the WS system I was able to create reasonable slops and run outs and then I could run the train with many cars (10+) although with a small layout and 15" to 17" curves too long a train went around the curve and looked poorly. Best of luck.
 
TrinityJayOne; I could only see that issue at a crest of a hump.

The biggest issue with grades isn't the grade, it's a sharp curve at the top of the hill: straight-lining! :(
 
I've been road testing my own grade conundrum for the past week and have found that my Atlas Dash 8 40B (2 axle trucks) was doing fine with the transitions on the bottom end and struggling on the top end. The most I could pull was 10 cars at 3% and only for about 3 straight line feet. Not an encouraging performance.

So here's my plan: Hit a steep 4% curve on the low end and taper it down quickly with the longest stretch of the run at 2% and just enough transition at the top to keep from uncoupling. I've got 80" to work with so it'll look like this:
Run Grade
12" 4%
20" 3%
38" 2% (leading into an 11" rad curve)
10" 1%

If my calculations are correct that should put me at about 2" at the top. I wanted more but this is really pushing it as it is. More testing next week to see if I can get it to work. I'm quickly leaning toward to view that my world would be a lot simplier without grades.

...But where's the fun in that?!
 
Latest test results on the formula above are really discouraging. I've seen no improvement at all. She gets into the 2% portion (barely 3 ft or so) and looses traction.

I taped and handful of big steel nuts to the top of my loco and that did get me to the top but there's no way I can add that much ballast to the inside of the shell. At this point my choices are scrape my whole layout plan, which i really don't want to do because I love my track plan and my 8 yo really wants an overpass. Or restrict myself to an 8 car train.

Is there no other way to improve traction?
 
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My Dash 8 isn't fantastic at grades either, and that's the 44CW with 6 axles, although it did better than what you've stated above. The thin bodies just don't have enough room for weight unfortunately.

Perhaps check your rolling stock and make sure that everything rolls smooth? I have one car in particular that has a lot of rolling resistance and will be getting some new trucks soon. The wheels roll fine when you lift it up and spin them with a finger, but on the track it will even stop rolling down slight grades.

Another option is to use multiple units, although if I recall correctly you are using DC so this makes it a bit harder.
 
Silverblade, the best way to compare those two locos would be to check for reviews to see how many ounces of drawbar pull they have. That would give you a relative comparison of power.

As Pete said, check your trucks for rolling qualities, or the lack thereof.:eek: Might need to do some cleaning and/or lubing with some powdered graphite. If that doesn't work, replacing the trucks or wheelsets may be required.

Another solution is to add more power, like Pete said. Can't get more prototypical than that! You could also break the train and run it up the grade in sections. The Chicago & Illinois Midland, for example, had to do that with heavy trains on the Petersburg hill. Of course, that would get old FAST, not to mention not really being practical.

If running multiple units without DCC, you will need closely matched units, which will probably mean lashups of the same model and manufacturer. Remember to put the fastest unit in the lead. This is not much of a problem, as long as the difference is slight.

Hope this is of some help, Bob.
 
Burlington Bob said:
The best way to compare those two locos would be to check for reviews to see how many ounces of drawbar pull they have. That would give you a relative comparison of power.
Click to expand...

Interesting. This is exactly something I've wanted to measure on my own. I didn't know there was a standard for it already. Is there a device of some sort that measures this? I think it would also be handy to know how much resistance a piece of rolling stock generates. Which gets back to your question about whether I have any drag alongs. I do, but at 8 cars, I'm running just my smoothest MTs.
 
Model Railroader uses that as a measure of comparison when doing their product reviews. I don't know how they actually go about measuring them but I think this would be a good bit of info to have available to the buying public. But that might lead to a major drive to see who could put the most traction tires on a loco at the expense of reliable electrical pickup. Sort of like seeing who can make the most powerful 4x4 vehicle. I don't think that would be the best result for all concerned. But if that was made as an option, then maybe that would be a good thing.
 
From my limited experience with traction tires I really don't like them. Call me crazy but it kind of cheapens a train for me because it feels like cheating. Personally though I don't mind that not all my engines can pull 15 cars up a grade, because in MRR terms 15 cars is still a decent train. Hauling 100+ cars might be prototypical, but it's rarely going to be practical. :)

Anyways, back to the subject at hand! It's entirely possible to find the drawbar pull without some fancy proprietary tool as it all just comes down to physics. It can be calculated, but that involves multiplying the total drivetrain gear ratio by the motor's torque figure and other maths-related things. The easier option is to simply measure it yourself. Back in high school I remember using these force meter tools in science and I've been meaning to track one down. They're very simple, basically just a spring scale with a readout in Newtons. I just checked on ebay and the smallest one I could find (2kg/20N) will set you back about 10 clams. Alternatively, there's this, which is the exact same thing but with a digital readout and the convenience of selectable units. There's no time like the present so I just purchased one. :) Plenty of other manufacturers make similar devices, but all the ones I found were designed with much larger forces in mind (some went up to 5,000N).

Because physics is excellent, the same device can be used to tell exactly how many cars your train can pull in a given situation by pulling said cars with the meter. For example if you pull 10 cars up your grade and the meter reads 100g, a loco that gets a reading of less than that doesn't have the tractive effort to pull that train up that grade. Can't wait to find out exactly what my trains can do! :D
 
Pete, I've looked at that pull meter and it really is the way to determine what a loco can pull. Please let us know how well it works (maybe a new thread).
 
I probably will as I can't find any existing threads on it.

In the mean time, I wanted to test SilverBlade's situation but I don't have any risers, so I just put a makeshift grade on my test layout by raising one edge of the baseboard and adding an unused section of ply so I could make a long straight section. The wood is of a pretty bad quality and quite warped so the grade actually deviates a little bit, but it averages out to 2.9% (70mm rise over 2400mm run).

I currently own 26 cars, a small number of which are a bit light, and two of them are terrible rollers. I didn't bother testing my SD24 or GP39M because I know they can't even get this train started, nevermind pulling it up a grade. :rolleyes: I did test a lone F45 though, the result of which is below for your viewing pleasure.

[YOUTUBE]9HLFtBwxMrc[/YOUTUBE]

Not a bad effort! :eek: Obviously if I added one of the other F45s it will reach the top, jump off the end of the track and probably continue through the wall. :mad: :p
 
That pull scale is definately on my list. Thanks for the link. I'm amazed out the difference in power between these locos. Whose the manf for your F45? I get what you're saying about traction tires. On the other hand I am facing some pretty crappy choices here:

Take my entire track plan (which I really like) back to the drawing board and expand my benchwork substantially. If I had room for that I wouldn't be working in N scale to start with.

Or go on a shopping spree for $100+ locos until I find one with some gonads and consequently bench my present one which has a real sentimental value to me.

Or run 6 - 8 car trains which makes me feel like I'm stuck in the Bachmann / Tyco starter set club.

If I can find some rubber treads, I'd be willing to try it (just this once). My 2-8-0 has them and it runs better. Not a lot better but well enough to get by.
 
SilverBlade said:
Or run 6 - 8 car trains which makes me feel like I'm stuck in the Bachmann / Tyco starter set club.
Click to expand...
This made me laugh :D

You're right to be amazed because it is a pretty massive difference that the weight makes. I ended up trying my SD24 and as expected it couldn't even get the train moving. A lone Kato F7 could only get up to the turnout (about as far as the F45 was at the 17sec mark), then when I added a B unit it performed exactly the same as the lone F45. Athearn makes the F45s, they did a rerelease of new road numbers a few months back and that's when I got mine (look for the ones that say "Announced July 2010"). The DC versions were about $70 each online.
 
Yesterday I fixed one of the terrible rollers, improved the other one (MT trucks were too short), and vastly improved some others that were ok but not great. I also replaced the couplers on some other cars, taking my freight consist up to 29 cars. I retested the F45 on the grade and it got all the way to the top, although it was starting to struggle a bit. The pull meter hasn't arrived yet and it likely won't until Friday/next week as we have a public holiday tomorrow.

Any developments on your grade problem, SilverBlade?
 
TrinityJayOne said:
Any developments on your grade problem, SilverBlade?
Click to expand...

My Athearn BN F45 is on the way! Well, I should say it's paid for. 2 days later I still haven't gotten a ship notification. Still brainstorming my track plan. Shorter trains running at faster power settings vs a bigger layout. I keep going back and forth. My latest redesign has some huge payoffs including a really long 2% slope, but the trade off is having to use 9 3/4" radius turns - something I haven't been open to before. I want to run some intermodals and I love long freight cars in general, so I'm not too sure about that.

One new discovery I'm excited about trying: Bullfrog Snot (OMG, you gotta hand it to the guy who thought up that name!). I've seen nothing but good reviews of the stuff, many of them quite dramatic. If I had heard of it before hand, I'd have probably delayed on the F45. Curiously everyone is talking about applying it on steam engines and practically no one is using it on diesels. Less effective on smaller wheels? I donno. Anyway I have high hopes.
 
A wise purchase! Where'd you get it from?

The Bullfrog Snot stuff basically seems like liquid traction tires. I've seen a lot of people swear by it but I'm not keen on the idea of removing pickups from my trains.
 
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