Some say that 4% inclines for diesel is too troublesome and unrealistic. Should I avoid the likely derailments, shorter consists and other issues by ripping up the one inch foam and putting it as background? The plan is to have the consists climb that incline and remain at that elevation for about 60" before droopping an inch.
Interestingly, I have seen plenty use 4% risers without issues. Someone here mentioned that diesel tends to do better in inclines than steam (I have the former). For grins, I put a diesel on the incline with a few cars and they didn’t roll back or decouple. That gives me some hope that I can keep the current arrangement.
I have two HO 3½% grades, one is a normal curved 32” radius to straight to curved 30” the other is a 32” radius helix. Never had any problems with either steam or diesel.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
I planned to do a 4% grade, then I found that the grade is compounded with curves which have increased drag (friction). My 4% grade with curves calculated out to 6.6%. I was using steam, and only my geared steam could make the climb and only one could pull 6 cars.
So my suggestion is to test it before you decide. I got an 8 foot 2x4 screwed down some track, hooked it to my power, and raised one end 6 1/2 inched for the test. Hopefully someone will post the formula for determining the calculated grade for any curves you have.
As a result of my testing I reduced my grade to 3%. You can spread your risers out to make a 3% grade if needed.
I would be more concerned about the length of the vertical transitions than the grade. There is a formula to determine the length of vertical easements. Here is a previous thread on the topic:
The PRR ran the Madison (Indiana) grade possibly into the Conrail era. It was 5.89%!
A pair of specially fitted SD-7s were used on the grade, 8588 and 8589. Equipped with special rail washers. Trains were limited to fifteen cars and the locomotive had to be on the down-hill side.
I’d suggest you run test trains to see if they’ll behave as you want them to on the grade. I had a 4% on my layout. Going up grade was fine, but coming down caused problems. The cars would slack-and-bunch, slack-and-bunch, all the way down. (I believe the specific cars I was running may well have contributed to this as well.) I was running at low speeds. I decided to make that grade into a vehicle road, as the surrounding features allowed it. Looks great that way too.
Some locomotives also had issues with the weight of the train pushing on the gears and actually causing an unwanted eratic braking effect, also when coming down grade. Do enough testing at the speeds you’ll be operating at, and with locomotives and train cars you expect to run on it to prove if will work before making it permanent. Dan
Personally I’d rather stick with grades under 3% but I prefer to run longer trains. If you plan to run shorter trains then you may be ok. Just like in real life, a 4% grade in HO will be somewhat restrictive, but in modeling we often have to make those kinds of limiting choices.
Of course, they once sent one of those locos to the shop and the shop crew had no idea what all the extra brake gear was for so they never hooked it up. The first crew to ride that loco down had a rather scary surprise. It was a story in Trains or Classic Trains.
His plan probably requires it for some reason or another.
I have a curving (~25" radius) 3-1/2% grade on my layout. I run trains of roughly 8 cars plus caboose pulled by medium steam and early diesels. It’s pretty much the limit of what my Bachmann 4-8-2 can pull up the hill. My Broadway 2-8-2’s (have traction tires) or my Proto F-3’s, however, can handle plenty more. I have tested that. It’s a compromise I had to make and am happy I did. Mock it up with your intended consist and give it a shot. You might be pleasantly surprised.
As others propose, I think running some trials with the actual equipment that you are planning to run makes the most sense.
Personally, I started building a layout that had 2.5% grades, compounded with 18" radius curves, and that proved too much for my steam engines (4-4-0 and 2-6-0) to run consistently. I found that I can run up 1.8% with reasonble length consists of about 5-6 cars. Per a calculation that originates by John Allen, you can calculate the additional drag in curves as 32/r, in my case 18", which results in a coefficient of 1.78, which then should be added as a percentage to the actual incline. This means that my incline in those curves is equivalent to roughly 3.6%. You should definitely consider assessing that aspect (from your post I do not see if you are in fact running a curve).
The second aspect someone mentioned is the length of transition, since abruptly going from 4% to flat would definitely cause unwanted uncouplings. E.g. before and after the actual inclines you are running, you would need to transition with lower inclines, making either the 4% even steeper in between, or would not get you to the height that you actually want to achieve (do you really need that height?).
First off, this is a hobby, not a 401k. You need to look at all the money you put into the hobby, even on stuff you tear out, as money that was spent on entertainment.
Second, there no absolutes, no one size fits all. Everything is a tradeoff. You’ve already built it, it would be silly to tear it down before testing it.
FWIW, with an Athearn HO RTR SD45 I pulled 18 BLI 70-ton hoppers (granted, not very heavy cars) up a 5% grade. It is my opinion that a lot of these “rules” are rooted in old experiences with old equipment.
I used Woodland Scienics 4% inclines to go up 2 inches, short “Y” and switch back on the level, then up two more inches to an iron ore mine. !4 years later no derailments, no percieved engine damage.
The trains are short, as it is a one stop switching branch, but it works, with no deliberate transitions, with ore cars, or box cars or gondola.
Yes, but what reason? Is this a logging railroad, or a class 1?
A figure 8 over and under?
There may be alternatives to a 4% grade. For example if it is a figure 8 the over track can have a 2% up grade and the under track can have a 2% down grade. The separaton at the crossing point will be the same.
Carl: You’re right about it not being a 401K but I hate wasting money. Hard to enjoy when have three young kids. They want to see the layout and I want to show them but trying to ensure it all looks ok.
I decied to not take chances and remove the 1" foam. The foam can get used elsewhere. While fun to have such an elevation change, I think the chances of potential issues out-weigh the enjoyment or desire to test the laws of physics. Thanks all for your help!
A failure to communicate? Let’s assume that a 4 inch separation is required. Let’s also assume that we have 100 inches of length to get to that separation (not including any transitions at the beginning of the grade). So that would be a 4% grade.
On the other hand, if the track to be crossed can be depressed below grade by 2 inches, then the track crossing over only has to go up 2 inches. We end up with the same 4 inch separation but the grade for each track is only 2%.
The ability to have a track go below grade is one of the advantages of open grid table construction.
