I am having some trouble with HO scale 80' boxcars. My mainline radii are 30" and 28" respectively. When the 80' boxcars are on the 30" radius track, they catch on and drag along some tanktrain cars (and others for that matter) that are on the inside 28" radius track. The track is on cork roadbed, so the spacing in between should be fine. Do the prototypes have these problems? Does one train have to wait on a straight section of track while another passes around a curve up ahead? Or do I need to space out my two tracks some more?
I'm beginning to realize that Windows 10 and sound decoders have a lot in common. There are so many things you have to change in order to get them to work the way you want.
THat's too close for those long cars. Let me look something up, but you should probably be more like 2.75" apart.
OK, maybe more like 2.5" to 2 and 5/8". Got an old NMRA reference that slice this a couple of different ways. However, it needs to be somewhat more than 2" if you're running long equipment, even if arouund 30" to 32".
Mike Lehman
Urbana, IL
John Armstrong's book Track Planning for Realistic Operation has the following table based on the inner radius
He cautions that articulated engines may need more and puts in a disclaimer about average rolling stock, appropriate for the curvature.
In prototypical operation, with Murpheys Law in constant effect, it would be disasterous to have lines too close together and a waste of dual tracks.
Henry
COB Potomac & Northern
Shenandoah Valley
NEVER have track centers at 2.0 inches on curves. Only straight track.
If you had read John Armstrong's "Track Planning For Realistic Operations chapter on Minimums to you could have avoided this situation.
2 1/2 inch centers is probably a safe distance for curves to avoid interference of long cars on adjacent tracks.
Rio Grande. The Action Road - Focus 1977-1983
i assume that you used the cork roadbed for spacing ....
it's okay on straights, but not enough on curves
you have to go wider on curves to allow for overhang
BNSF UP and others modelerDo the prototypes have these problems?
.
The prototype does not have this problem because they use what would be like 120" radius curves!
We have this problem. Sorry.
-Kevin
Living the dream.
Yes, at 28" and 30" radius you need some extra clearance on curves for cars 80' long.
You have to get into the 36" radius and above range before you can keep track centers at or near 2" on curves.
I have built several layouts with 36" and 38" curves on 2" track centers with no clearance problems - but, while I own some big articulated steam, I have never owned a UP Big Boy.......
Sheldon
PS - as I take a look at the current NMRA Recommended Practices on this, it appears they have greatly increased their recommendation from years ago - I will be checking my orignal 1968 set of RP's for comparison.
Since 2" centers above 36" radius has always worked for me, I am not likely to change. One factor may also be that I use easements?
30" and 32" with easements did not work, I had to extend it - and it was already NOT exactly parallel, the center spacing was more than the 2" difference in radius. But, it was thoroughly tested with the longest cars that might run BEFORE any track was fastened in place permanently. That's thge key - TEST, don't take someone's word for it. ANd it's not always just the longest cars. Depending on the truck centers or any extrended drawbar, a car that is not quite the longest one might have the most overhang.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
BNSF UP and others modelerThe track is on cork roadbed, so the spacing in between should be fine.
I agree with wvg-ga, don't let the width of the road bed you used, judge radius spacing.
I have a siding, and I maintained a 2 1/2" with the main. It follows the main around a 24" radius, and no problems.
And easements, the space given before the curve, so you enter it gradually, and "ease" into the curve, and out of it, are real important. You want to avoid going from a straight track directly into a radius, you need to "ease" into it.
Mike.
My You Tube
ATLANTIC CENTRALSince 2" centers above 36" radius has always worked for me, I am not likely to change. One factor may also that I use easements?
It may have mainly to do with the equipment you are using. Longer cars, those beyond Plate C, and articulated engines may need a skoche more, even at 36" radius. You likely have none of those things, so it works for you. Maybe not for everyone modeling every era with every piece of equipment.
Not to mention that even a small mistake in track laying by a newcomer (as is the OP) could create unexpected issues.
The NMRA standards are a good place for newcomers to start. Some long and wide modern equipment likely falls under "Class 1a"
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cuyama ATLANTIC CENTRAL Since 2" centers above 36" radius has always worked for me, I am not likely to change. One factor may also that I use easements? It may have mainly to do with the equipment you are using. Longer cars, those beyond Plate C, and articulated engines may need a skoche more, even at 36" radius. You likely have none of those things, so it works for you. Maybe not for everyone modeling every era with every piece of equipment. Not to mention that even a small mistake in track laying by a newcomer (as is the OP) could create unexpected issues. The NMRA standards are a good place for newcomers to start. Some long and wide modern equipment likely falls under "Class 1a"
ATLANTIC CENTRAL Since 2" centers above 36" radius has always worked for me, I am not likely to change. One factor may also that I use easements?
Agreed, I model 1954, I have only few cars longer than 75', some 80' cars, and no 85' cars.
Biggest loco is a B&O EM1, but a modern model, with double articulation, as are all of my articulated steam. Longest diesel, E8, longest rigid steam USRA 2-10-2.
Upon closer investigation, the new NMRA RP7 is not that different from the old S8.
There is no question that safe may be better than sorry and down at 30" radius there is no question about the need for extra space.
cuyama,
I may be a fairly new member of the forums, but I got started on this hobby a few years before joining. That, and I am on my third layout, which is why I had enough sense to fasten the track down on my current layout with track nails. I learned my lesson in making poor track laying mistakes, so this time it will be an easy fix. Especially since now that I have these great responses I know what to do...
Thanks everyone!
It takes literally minutes to pin down curvature in flex track at certain various radii and clearances and then run trials. You don't even need to use roadbed of any kind, just tack curves of flex down and let the real clearances tell you what you can get away with when you run combinations of whatever locos and rolling stock you intend to use.
I know that my Rivarossi Allegheny, the H-8 2-6-6-6, is the one beast I have to be careful of with respect to curves due to cab overhang and the engineer's injector overflow tube. When I am situating tunnel portals and tracks onto bridges near curves, I grab that one locomotive and make it run over those places before I let any PL300 dry. Where twinned mains run along curves, I run that one locomotive backwards and forwards along them with Walther's heavyweights sitting along the apex of the curves on the other track. Steamers behave differently when backing. The cab overhang can get worse.
But there's something else. If you make a mistake laying those nested curves later, and make them a bit tighter in radius or bring them even 1/8" closer together than you had trialed, you may be in for an unpleasant revelation. So, when you mark out the centerlines, make darned good and sure you have them right. Use a trammel, or a large compass, or a string and nail. Do not fudge your curves when you intend to keep clearances really close.
I have a double mainline with 32" radius curves.
To prevent overhang problems, I do three things during track laying.
One, I use Ribbonrail Metal Track Alignment Gauges to ensure consistent curvature.
Two, I use a pair of 80' boxcars to test the clearance as I move along.
Three, I set the distance between the two mainline tracks at 2 1/2" on center in the curves.
Rich
Alton Junction
BNSF UP and others modeler cuyama, I may be a fairly new member of the forums, but I got started on this hobby a few years before joining. That, and I am on my third layout, which is why I had enough sense to fasten the track down on my current layout with track nails.
I may be a fairly new member of the forums, but I got started on this hobby a few years before joining. That, and I am on my third layout, which is why I had enough sense to fasten the track down on my current layout with track nails.
How could you be on your third layout and not know something as basic as minimum track centers on curves? Good thing you used track nails so you can take it up and re-lay properly, vs adhesives which for that reason I don't care for.
Again, get and read John Armstrong's book Track Planning. Otherwise you wouldn't be on your third layout and still making this mistake with track centers too close on curves. By the time I built my first layout back in 1990, I had read and reread that book. People usually recommend a 4x8 for a "get feet wet" first layout but mine was 16x19 hollow L. Having read John's book I had the confidence that I could design and build a fairly complicated track plan with easemented minimum 30" radius curves and Max grade of 2.5%.
Get the book and read it, love it, know it. Test will be next Friday. Be ready!
[quote user="riogrande5761"]
The previous 2 were using LL, bachmann, etc sectional track and they weren't serious layouts. They were on a 4x8. Thats why.
Does the prototype have these issues? Yes in a sense. Extra wide loads (so called dimensional loads) move under restrictions in double track territory. I once had the chance to see an actual Schnabel car in action and it was moving slowly from passing siding to passing siding so that it would not be encountering anything on the other track of a double track main. The DS was in contact with all trains on that route informing them of the issue.
On curves an 80' car -- any long car or engine -- becomes an extra wide load in a sense because of the overhang.
I have a 2" spacing on my double track main layout. I wanted to retain the 2" spacing on curves because my curves are not where the prototype curves were -- my curves are because my basement has walls that must be avoided So in a sense my curves are not modeled curves.
I run passenger trains so I needed to find the two radiuses (radii?) that would enable full length passenger cars in trains to meet or pass each other with track laid to 2" centers. I was familiar with John Armstrong's chart but he did not carry it forward to radii that could tolerate 2". I had a bunch of brass flex track sitting around so I started to construct a series of 2" radius concentric circles that 85' passenger cars could manage. (It was actually kind of neat looking.)
36" and 38" radius curves as double track on 2" centers -- too close together. Sidescrapes were possible. In part it depended on the cars which do not all have the same truck centers.
What I found through trial and error: 38" radius and 40" radius could work but it was really close and would call for very perfect radius track laying and even then maybe not each and every possible combination of cars on opposing trains would make it. I decided to be safe and go with 40" and 42" but I think 39" and 41" would be fine.
Dave Nelson