You see, that was exactly my point. Your rolling stock is FINE with those radii (3x rule), but your Locomotives are pulling your rolling stock off. If you went with shorter locomotives, then you wont have to modify the couplers or have as many issues with coupling than if you continue to use locos that are too large for those radii.
What JW doesn’t tell you is that he has had to modify alot of his locos to allow them to squeeze through tight corners.
David B
Not true! I only had to modify one, the AC4400. All the others are stock and have Kadee #5 couplers, with the exception of the SDP40F’s, they have Kadee #148 whisker couplers.
Hello ??? What scale are we talking about here ?
Not knowing if you’re in HO- or N-scale makes it impossible for any of us to properly answer your question. There is a HUGE difference between 18" curves in N-scale and 18" curves in HO.
It seems obvious that people have been talking about HO scale. I don’t think there would be much debate about N scale or O scale 6 axle diesels handling 18 inch curves. But I could be wrong.
Harry,
My question was meant for the OP.
I realise everyone who answered PRESUMED he was modelling in HO; but the OP never says what scale he’s modelling. For the sake of clarity, accuracy, and for those new-comers to the hobby who might not know any better, it is important to indicate what scale you’re modelling when asking such questions.
I will venture that most six axle (HO-Scale) diesels will operate on 18" radius curves however your posting infers that you are moving from a 4X8 to a room sized layout so I would like to querry why, if you have the room, you would want to operate six axle diesels on that tight a curve. Keep in mind that those six axle diesels are long and on an 18" radius curve there is going to be a lurch factor with the trailing car behind; if you insist on operating six axle diesels and you have room for 24" radius curves by all means USE THEM! Remember, the tighter the curve the shorter the train you are going to be able to operate around it and I don’t care how you cut it an SD40-2 looks a little ridiculous lugging around a ping-pong freight!
Even if you’re not going to use it on the layout when you build it, I would get some Bachmann or Kato snap-together track-with-roadbed of different radiuses and see what will actually fit. I found on my L shaped switching layout that - using 16" wide shelves - I could comfortably fit in Kato 31" radius curves and could probably go a little higher. When I tried it with 12" shelves I could still get the 31" in if I did it just right, but 28" would be a little easier.
Anyway, you might be surprised what will actually fit in your space.
Here are some points to keep in mind when you are planning your new layout.
First, there is an absolute minimum radius for each piece of equipment when it is running solo. This is set by how the running gear interacts with the track geometry. For a diesel locomotive, will the trucks swivel enough to keep all the wheels on the rail without hitting something or causing a bind in the universal joints in the drive train? Will the truck design allow enough side play in the center axle to prevent the flanges from climbing the rail? You can test all these things quite easily, but do test to avoid being sorry. Keep in mind that some allowance should be made for less than perfect trackwork on the actual layout. In my experience nearly any six axle diesel will physically go around an 18" curve.
Then you need to take into account what happens when the locomotive is coupled to it’s train as well as what cars are in the train. As the train enters a curve there is an offset at each pair of couplers. This offset can cause real problems and is more often the source of derailments than the fact that the locomotive or car won’t “go around” the curve. Interestingly, the use of an easement, or section of track of gradually increasing curvature, really makes a difference here. In fact, an 18" radius eased curve will have less offset problems than will a 24" curve without easements. Easements are a space bargain and allow your equipment to perform optimally with the least space requirement. The length of the easement should be about the length of the longest piece of equipment you plan on operating. You can find more information about easements on the NMRA website. If you are mathematically inclined, you can use the proper formula for the railroad spiral to shape the easement, or you can use a cubic spiral. Most people lay them out by eye or by using a bent stick.
You can use easements with sectional track should you decide to reuse the tr
You don’t mention how your room is designed, but you have room for a 4x8 right? Is it possible to build around the walls, so you could actually have a larger than 4x8 layout, and just operate the layout from inside? I did something similar to this when I was renting a duplex many years ago. I started out building with 2 4x8’s, and was going to cut one into a 4x6 and a 4x2, then make a sort of “U” shaped layout. I didn’t want to attach anything to the wall since I was renting, and I needed to be able to get all the way around the layout for access, or else I might have been tempted to just butt those two 4x8’s together to make a 8x8 layout. But shortly after making my original “U” shaped layout, I came up with another idea. I bought some additional lumber, and closed the “U” up on the back side. Also while I was at it, I dropped the level of that wood down, kind of open grid style and made an area for a bridge. By doing this I had doubled my mainline run, made a large open area for a small yard and engine terminal, and had room for several industrial leads, a passing track, and if I’d ever gotten that far, a good bit of scenery. The layout was dismantled shortly after laying all the track, wiring it up and weathering it, but I did get a little run time before I had to tear it apart. Most of my curves on this layout were 22, 24 and 26 inch radius. There may have been a couple broader. One or two of the industrial leads had a smaller radius maybe 18 or 20, but nothing sharper. Also by building this layout as an “open pit” style layout, it forced me to run it from inside, and I could not see the entire mainline in one view, which enhanced the illusion that it actually came from one point and went to another. Also I was able to run longer trains without it look ridiculous (seeing the locomotives chasing their own caboose).
At o
I started out [many years ago] with a Hornby OO train set that had the standard 18" radius curves. I soon added a second track that used 21" radius curve sections. My “standard” 4X8 soon became 5X10 feet so that the outside track wasn’t so close to the edge of the layout. At age 10, I started modelling North American HO. Remembering I never really liked the appearance of my OO passenger cars on those 18", or even the 21" radius curves, I went to 24" minimum curves and started using flex track. Early in that decade, my family moved into a home where I was able to acquire a corner in the basement for my hobby. That is when I moved from the confines of a fixed rectangle 5’X10’ layout to a sectional layout, similar to the one described and illustrated here in an earlier posting. My minimum radius became 30" and I’ve never looked back (umpteen layouts later). So, after all this discussion about 18 versus 24 inch radius curves, everyone is right one way or another in what they have stated. But don’t fret too much about this topic today. A lot of you, if not most, will migrate to broader curves eventually I assure you. Have fun on the way.
Cheers, Marty on Vancouver Island
I think Marty is largely correct. I built my original layout with EZ-Track 22" curves, and was I ever glad I had the foresight to purchase the wider turnouts as well. But…when the time came to seriously consider another layout, my first thought was, “I will not have a curve shallower than 24”, and on the mainline nothing less than 28" so that longer passenger cars will look good." I have no regrets, and would love the space and layout where even yard curves were in the order of 28", with mains minimally at 32". Each new layout gets the “gotta do this” treatment of one kind or another, and for many of us who tend to be more rail fan-like, we want the broader mainline running.
Realistically, one has to do with what one has in the way of space, and I am sure there are many happy modellers who enjoy curves a whole lot tighter. I am sure they would like more, and would quickly dispense with a more limiting track plan if they had the chance. I was no different.
-Crandell
[soapbox] From my experience, a six axle power unit WILL run on an 18" radius curve, but watch the length of you cars. Any 86’ cars will not take an 18" radius. Even some shorter cars have problems, such as 75’, but I don’t know about the 60 footers. I have two radii on my layout, a lower “rathole” track that has one section at 15", but the rest of my trracks on the upper level are 24". Even on the 24" I have a problem with 86’ equipment-good thing I only bought one to experiment with[:(]
I am using mixed radius with no problem. In fact I also have an area in a steel mill where I have 12" radius curves and encounter no issues. A SW1500 and GE 44 tonner make the turns just fine.
If you can support an additional foot in width, most of your problems go away. I have an area that is 5" wide and run a double track turn around it with no problem at all. Designing in an extra foot makes a world of difference- but if you are committed to a 4x8, you can certainly run decent sized gear.
On my N scale Kato unitrack layout the smallest radius is 19’’ which is about equal to 38’’ radius in HO scale . Six axel diesels look great , so do my 85’ california zephyr pass cars. My largest and most common radius is 28’’ or about a 56’’ radius in HO. How often do you even see anything close to this in HO?
It looks so much better with larger radius curves. That is one of the main reasons I am an N scaler.
My Proto 2000 E6 runs fine on an 18" radius, but when the Walthers heavyweight passenger cars box says “minimum 24” radius", you better beleive it.
I did the same as you did. I purchased a track plan book and ordered the material list from the manufacturer. This layout worked ok for a beginner but when I wanted to upgrade my 40 foot cars to the 50 foot and longer and also use 6 axial locomotives I found only a few locomotives would work without derailments from time to time. I believe the only 6 axial I had that would run good on it was the old athearn SD45 which was shorter than the SD40-2. after a few years of frustrating derailments, I almost gave up model railroading. I would suggest that you do at least 22" radius and would recommend 24". That way when you decide to get the longer cars down the road (and you will) you will have a layout that will run them without derailments and the frustrations will not be a factor in you giving up on model railroading.
Good luck
Eddie
Cat375 - I have had a 4x8’ layout and run my Atlas Trainmaster (a long 6-axle engine) through the 22" and 18" radius sections with little trouble BUT find that the #4 Atlas switches that I used were trouble.
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