I'm looking at a 3% ruling grade as the track transitions approximately 4" in a 12 foot span. Do any of you have experience with a ruling grade near 3%? Mine is a smaller layout geared for switching and ops meaning shorter trains so I'm assuming this won't present too much of a problem and I don't think this is anywhere near a deal breaker.
Although the calculated grade itself won't change from one scale to another, I have noticed that a 2% grade in a helix affects my N-scale locos more than a similar 2% grade affects the locos on my HO switching layout: individually, my n-scale NW2s and SW900/1200s can pull 6 or 7 properly weighted cars up my 2% helix without slipping; but the smaller locos on my HO switching layout often pull 9 or 10 cars up a 2% grade. My guess is that a 3% grade would cut the numbers down even more, but HO locos will still be able to pull more cars than the N locos. If you consider 5 or 6 cars to be a short train, then you shouldn't have any problems with a 3% grade; however, if you define a short train as 9 or 10 cars (perhaps, half of a 20-car train?), then loco wheels spinning on the hill may be a problem. Pulling power varies a great deal from one loco to the next, so if your smaller locos have issues, there may be medium-sized switchers that could work the grade comfortably without forcing you to double-head or assign larger mainline power to do the switching job.
Just wanted to add: A grade on a curve adds drag to any train. I found out the hard way years ago. I Built an Ho layout with a 27" rad. curve in it. Line already had a long straight run at about a 2.75 %. But the pull upgrade on the curve made trains behave as if it were a 3.50-75 Deg. grade. I was Ok anyway as I also only ran short trains on this bucolic branch/bridge route (now long gone due to having to move)..So, don't forget to factor this in if you too wind up with a curved grade... M
karl, I must agree that 3% is 3%, however I've modeled in scales Z thru O. Some locos will NOT make the grade. Jim
Thank you all for the helpful replies. Part of the grade will be on a 90 degree curve. But again, trains won't be real long and in most cases will probably have two powered units. Sent from my iPhone using Tapatalk
I believe you will encounter some serious problems with a 4" vertical curve on either end of a 3% grade. I feel that about 3"/%grade is going to be the practical minimum for any low-hanging couplers with their glad hand/trip pins left in place. I had a Bachmann Spectrum Class J 4-8-4 whose lower pilot edge bound quite severely on my generous transitions on an older layout. I actually had to shave some of the plastic. Coupler trip pins are often worse than Bachmann's oopsies.
I'm confused by your statement. Particularly the 4" part. The grade is 3% and part of it will be on a curve. I don't think the total rise has much to do with anything. Thank you. Sent from my iPhone using Tapatalk
COverton, Yeah, I too don't get the 4" thing. Moreso I never heard of a grade having anything to do with affecting pilots (cow catchers), couplers, gladhands, pins !! The only way this could occur is if you immediately went from level track to a say, an 8% grade with no vertical easement into it !! How does/did your 4-8-4 come to hitting (what ?) ties, frogs or guard rails, et al, by climbing a steep grade ??!! I know it's probably legal where you live but I'd suggest smoking it off line !!... M
When I was building my layout, starting over 30 years ago, I wanted a grade to purposely limit the number of cars that a single diesel locomotive could pull up a grade. I ended up with just over a 2% grade which limited an average locomotive to 14 cars plus a caboose. With this in mind, I build passing sidings long enough to handle that train length. Some diesels can easily handle more cars and steamers less. This grade also requires extra locomotives to be added if a longer train goes up the grade. In this video, the train comes up a two and a half percent grade out of hidden staging tracks to a level area where additional tracks come out of a town and yard. After about a three and a half foot long level run, it comes into the two percent grade which starts at the left of the video.
I found the easiest way to check was to build a small mock up and try it out. I found it reassuring to just use my locomotives and my cars on the exact slopes and curves I was planning to use and see if they worked. Sent from my Nexus 6P using Tapatalk
It seems to me that you'd not even need to test for this if you are constructing up to 3 or even a 4 % grade. I mean, of course no one, but perhaps a newbie would make such a grade, and only out of sheer newness to all the variables in the hobby and the 1:1 scale..With a 4 % or less grade, I don't believe any loco that exists or kadee coupler pins are going to be a problem in the first place...
That's a little harsh - there are many layouts that do push the higher grades (not to mention many prototype examples such as CPRs big hill). Not everyone has the space to stay below 3%, and there is a lot to be said about have a pusher district that actually needs pushers (or multiple units to pull short trains) Sent from my Nexus 6P using Tapatalk
Thank you for the comments. I appreciate them all. I'm limited to an 11x10 space so there is the natural weighing of complexities, trade offs, and what can be achieved with the track plans and space. The original track plan I'm following has a ruling grade of 2% but that limits the max height of the trains and ultimately to an era I don't want to be confined to. I want to run some more modern and taller rolling stock so that means max clearance and ruling grade needs to be bumped up. 3% definitely wasn't my 1st choice but it was a compromise. One really nice thing about 3% is that it's not 4% Sent from my iPhone using Tapatalk
Hey Gravy, (above), what's a little harsh ?! You're a little harsh on me, my simply trying to point out that over a 4% there just may be some bottoming out of pilot, pin, or glade hand if there is no transition (vertical easement) up to such a grade. Please read my post the way it is meant and not the way you want it to mean. No one said anything about any grade not being allowed to attempt by the builder, thank you ! ...M PS. I will not continue arguing over all this. Say what you wish. I'm outta here.......
Does the grade have to be integer? If you are only a little short on height, might a 2.4% or 2.6% grade be sufficient?
My Z scale layout consists of 3% grades (with broad 14" curves). No problem to run 16 to 20-car trains with 3-unit lashups on it. Dom
