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Post by edwardsutorik on Mar 24, 2024 6:27:48 GMT -8
Yup. The title says it.
I am wondering at members' experience in operating these cars. In particular, in yard and industrial settings--not so much main line.
What minimum radius would you recommend?
I'll add that the operation should include running with short cars adjacent, not just matching long ones.
Ed
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Post by cemr5396 on Mar 24, 2024 6:39:15 GMT -8
If you are running long shank couplers, (which most cars of that length have anyway, on the prototype at least) you can get all the way down to 18" in the right circumstances. I used to run Walthers auto racks with the swinging draft gear disabled and Kadee 156 long shanks on my old 4x8 when I was a kid.
Certainly if you go up to 22" you should have no issues whatsoever.
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Post by edwardsutorik on Mar 24, 2024 6:48:17 GMT -8
Brad,
Thanks for the response.
I think I'll add to the "rules" that swinging draft gear doesn't count--kinda planning for the future, and having to accept more prototypical coupler mounting.
I'll also note that a vast number of trailer flats do not have cushioned underframes/draft gear. The only ones coming to mind are the ones set up to handle containers.
I'm thinking "worst case" hear. Ya never know when some manufacturer will produce some new cool freight car that requires purchase.
Ed
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Post by Baikal on Mar 24, 2024 7:26:26 GMT -8
Yup. The title says it. I am wondering at members' experience in operating these cars. In particular, in yard and industrial settings--not so much main line. What minimum radius would you recommend? I'll add that the operation should include running with short cars adjacent, not just matching long ones. Ed
[Question is a spin-off from the current Free-mo io modular group discussions on the pluses & minuses of smaller min radius for smaller venues. Currently 42 inch on the "main". Also inspired by Industry-mo and the rouge switching module group groups.io/g/Mudliners]
To answer your question- it varies by car. But I'd say about 24 inches min radius for 90% of model 85-89 ft cars. They will look rediculous but they should handle the curve.
Free-mo or Mudliner industrial trackage (Not "main", not "branch") should not have a minimum radius, or it should be very tight, like 12 inches.
42 inch radius for the Free-mo main is already a huge compromise from 99% of prototype curves. Found only where geography or development forces such tight curves. Resulting in movements at slow speeds. So there should be little beef when having to compromise on yard & industrial curve radius too. Otherwise it's near impossible to model older and/or dense urban switching areas.
Some model trackage just isn't going to be accessable to longer freight cars. Just like the prototype.
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Post by Colin 't Hart on Mar 24, 2024 8:12:24 GMT -8
Joe Fugate researched and published info about minimum radius. For reliable operation with cars coupled being of a similar length, you want a minimum radius 2.5 times the length of the longest car. So in your case you're looking at around 30", assuming your cars are 12" long. If you want reliable operation for coupled cars of different lengths (ie 89' flat cars coupled with 50' box cars) then that ratio goes up to 3 times the length of the longest car -- provided you have swinging couplers. So in your case 36". If you want semi-scale width coupler boxes and different lengths of cars, then that ratio is 5 times, or 60". Consult issue 1 of Model Railroad Hobbyist if you're curious. forum.mrhmag.com/post/mrh-issue-01-jan-2009-12188025 |
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Post by bnsf971 on Mar 24, 2024 8:58:27 GMT -8
Ed, I've found 24" to be best, as far as minimum radius, and #8 turnouts. I've used #6s, but only as a ladder track. If you're planning to have opposing turnouts facing each other, things can get complicated quickly. Those longer cars really don't like S curves of any type.
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Post by riogrande on Mar 24, 2024 9:04:56 GMT -8
Ed, I've found 24" to be best, as far as minimum radius, and #8 turnouts. I've used #6s, but only as a ladder track. If you're planning to have opposing turnouts facing each other, things can get complicated quickly. Those longer cars really don't like S curves of any type. Same, I believe the manufacturer recommends 24" minimum radius as well. I'm using #8 turnouts on the main and for crossovers and #6 for ladders in the yard. I have heard that Tangent 86' Greenville boxcars don't like S curves. I have a gentle s-curve I was concerned about so I ran a couple Tangent 86' Greenville's though and it was no problem. It was a 36" curve though a #8 into a 33" curve.  |
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Post by lvrr325 on Mar 24, 2024 9:14:40 GMT -8
I found that some of the cars, Atlas 89' flat cars for one, physically can't do much under 24" radius because the wheels hit the frame and it would just derail. I relaid a few curves to a larger radius (initially did not intend to run long cars) and they go through okay now.
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Post by edwardsutorik on Mar 24, 2024 9:41:51 GMT -8
I just assembled some Kato track: 31" radius and straight.
I ran an 89' flat (with long-shank couplers) connected to a 30' long caboose. In the turn, the 89' car's coupler was swung back to centerline (by the other car) such that there was very little additional swing available. From that, I would think 30" is the absolute minimum. And would, incidentally, recommend against 24".
Ed
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Post by GP40P-2 on Mar 24, 2024 9:57:28 GMT -8
Looking at your NorCalF Freemo standards document right here in front of me, it is already covered, 30" branchline, industrial, and secondary; 42" minimum on the main. Tracks are supposed to be designed with consideration for the types of cars that will be using them. Conversely, pig flats and auto parts cars need to "stay in their lane" and out of the tight areas.
That standard was developed closely with the San Luis Obispo and southern California Freemo groups, with DNA from the European Fremo, so it really doesn't need revision.
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Post by cp6027 on Mar 24, 2024 10:58:24 GMT -8
For yard and industrial tracks it is less about minimum radius (although it is still important) and more about turnout size and how much tangent (straight) track is present between reverse curves (S-curves).
For example, although not always obvious, diverging through a turnout off the mainline and then curving back into a siding track parallel to the main creates a reverse curve. Using a larger frog number (shallower diverging angle) and increasing the track center spacing will both increase the amount of tangent in the middle of the reverse curve and lead to better operations with long cars when coupled to each other and also to short cars.
Ideally, in yard and industrial settings, the minimum tangent length between reverse curves/turnouts should be the length of the longest car expected to make that move
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Post by edwardsutorik on Mar 24, 2024 11:26:09 GMT -8
Looking at your NorCalF Freemo standards document right here in front of me, it is already covered, 30" branchline, industrial, and secondary; 42" minimum on the main. Tracks are supposed to be designed with consideration for the types of cars that will be using them. Conversely, pig flats and auto parts cars need to "stay in their lane" and out of the tight areas. That standard was developed closely with the San Luis Obispo and southern California Freemo groups, with DNA from the European Fremo, so it really doesn't need revision. Not for you. And not for me. But there's some folks who want to have an "industrial" standard. The idea is that they don't need sharp curves. I am sympathetic to that, but I don't want regrets--especially ones that come along later and bite ME. So I've joined up so as to represent my particular views. As for that 30" branchline curve you mentioned, I am sure that's a mistake/typo. The Free-mo standard (BL-S3.12) is 36", and NorCalF follows that standard. Ed |
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Post by GP40P-2 on Mar 24, 2024 12:42:08 GMT -8
Well mine are dated 2015 and show 30". I looked on the NorCalF web site, and the current (2016) version shows 30" on page 10, better get Gregg on that....
In the past, industrial/shortline would be considered "non-conforming" (not "illegal," unusable, etc), meaning that they could be used if they didn't hamper other operations. They could be put off the end of the yard, or someone could build a conforming junction module off the main to which the non-conforming/shortline/industrial modules could do their own thing.
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Post by elfan on Mar 24, 2024 12:56:06 GMT -8
Ed, I've found 24" to be best, as far as minimum radius, and #8 turnouts. I've used #6s, but only as a ladder track. If you're planning to have opposing turnouts facing each other, things can get complicated quickly. Those longer cars really don't like S curves of any type. Same, I believe the manufacturer recommends 24" minimum radius as well. I'm using #8 turnouts on the main and for crossovers and #6 for ladders in the yard. I have heard that Tangent 86' Greenville boxcars don't like S curves. I have a gentle s-curve I was concerned about so I ran a couple Tangent 86' Greenville's though and it was no problem. It was a 36" curve though a #8 into a 33" curve. I use #5s in my yards, partly as a space saver, partly to make the cars have that “condensed snake” appearance that was common in the 50s/60s era yard tracks left over from the steam era of shorter car lengths. Getting to your statement “Tangent Greenville 86’ boxcars don’t like S curves”, I found this to be true on the #5 crossovers if you stay with the standard length Kadee coupler in those cars. I had to replace them with Kadee medium shank scale couplers to get them to traverse those crossovers, since they don’t have the swinging coupler boxes some manufacturers use to overcome that issue. The standard short shank couplers worked fine on a #5 turnout, but not on the S curve of a #5 crossover. With the extra length of the medium shank those cars go through the crossover either being pulled or shoved with no problem, coupled to anything down to a 40’ car. I haven’t tried anything shorter as I don’t own anything shorter than 40’. I even found they would work in that tight crossover even if just one car had a medium shank coupler, but I replaced all. Tom PS. Tried to add a photo, but the site says an iPhone file is too big |
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Post by edwardsutorik on Mar 24, 2024 13:10:27 GMT -8
Well mine are dated 2015 and show 30". I looked on the NorCalF web site, and the current (2016) version shows 30" on page 10, better get Gregg on that.... My thought, also. That's where I'm trying to head the standards to. One guy just posted some photos and drawings of a module design that he likes that appears to use 12" curves and #4 switches (based on the prototype). Looks GREAT. It wouldn't contain "mainline" industrial track, so I just don't see a problem. It'll be 40' cars and teeny locos (SOMEONE must still have a Dockside). But I'm advocating the "mainline" to be able to handle ANY freight car, 'cause "ya never know". Ed |
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Post by bn7023 on Mar 24, 2024 13:30:30 GMT -8
What about on a typical S-curve crossover?  WalthersTrack Part # 948-83051 Code 83 Nickel Silver DCC-Friendly #6 Double Crossover -- Length: 18-3/4" 47.6cm; Track Centers: 2" 5.1cm |
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Post by edwardsutorik on Mar 24, 2024 13:49:34 GMT -8
What about on a typical S-curve crossover? WalthersTrack Part # 948-83051 Code 83 Nickel Silver DCC-Friendly #6 Double Crossover -- Length: 18-3/4" 47.6cm; Track Centers: 2" 5.1cm Since the curves are in the closure rail, you have 4 to 6 inches of straight track separating the two curves. Also, the length of the curve is small, so the reverse curve effect is somewhat lessened. But. This is why it's a good idea to have a high-numbered crossover (gentler curve, longer straight). A #6 double crossover is really pretty useless, except perhaps in a crowded freight yard or industrial tracks. A #8 would be much better in most circumstances. In my opinion. Ed |
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Post by hudsonyard on Mar 24, 2024 14:14:22 GMT -8
My 85' and 89' trailer flats do just fine on 30'' radius, i probably woudldn't go much lower than that. As stated above the BLMA/Atlas TOFC cars don't really like anything smaller than 24-26''
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Post by Baikal on Mar 24, 2024 14:20:00 GMT -8
Looking at your NorCalF Freemo standards document right here in front of me, it is already covered, 30" branchline, industrial, and secondary; 42" minimum on the main. Tracks are supposed to be designed with consideration for the types of cars that will be using them. Conversely, pig flats and auto parts cars need to "stay in their lane" and out of the tight areas. That standard was developed closely with the San Luis Obispo and southern California Freemo groups, with DNA from the European Fremo, so it really doesn't need revision.
If you can't model less than 30" radius in industrial areas, the industrial standards need to be changed. Or there'll be spinoff groups with some sharper, more prototypical, minimum radius curves.
On the prototype, not all cars can navigate all curves.
I was a RR yard conductor and spent a lot of time in downtown LA, where some curves were less than HO 30". Zoom in- Industry Map of Los Angeles, July 1925. North is to the right. A lot of this was intact into the 80s.
I worked this location a number of times. There are eight (short) street blocks with industries behind the loco which is on an approx 30" HO curve:
Some tracks with sharper curves were occupied only by switchers and 40 ft cars. How does Free-mo allow modeling of such areas?
The Free-mo "main" at 30 inches is already a major compromise from 95% of prototype curves. Why not allow tighter industrial track curves? These are tracks that terminate at industries, and some may be distant. No thgru cars / trains.
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Post by edwardsutorik on Mar 24, 2024 16:28:21 GMT -8
Baikal,
I must thank you for posting the link to the railroad map of LA. I tried looking for something like this online, and couldn't find it.
When I was about 4, my mother had me in tow when she went to the giant Sears store in LA. There was a switcher working the cars at the building, and she convinced one of the crew to give me a tour. I remember it was scary loud. And I remember him pointing out the sandbox. Which I found ridiculous--he's a grown up, and only kids play in the sandbox. After that, I felt he was blowing hot air and trying to snow a kid who knew better.
I've been wondering which railroad's switcher it was--apparently UP.
Anyway. Back to the topic at hand.
I am quite sure that no one is proposing ALL the trackage on these modules must be 30" radius. Or whatever. Only the "main line", through which the cars must be distributed. As I mentioned a couple of posts ago, one guy wants to have 12" radius on his module. Since the "main" doesn't go through it, I don't see a problem.
Ed
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Post by locochris on Mar 24, 2024 17:34:21 GMT -8
If 42" curves are still a compromise from prototypical mainline curves (not sure what Free-mo means), what inch curves would you need to use to stay completely prototypical?
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Post by Baikal on Mar 24, 2024 17:53:18 GMT -8
Baikal, I must thank you for posting the link to the railroad map of LA. I tried looking for something like this online, and couldn't find it. When I was about 4, my mother had me in tow when she went to the giant Sears store in LA. There was a switcher working the cars at the building, and she convinced one of the crew to give me a tour. I remember it was scary loud. And I remember him pointing out the sandbox. Which I found ridiculous--he's a grown up, and only kids play in the sandbox. After that, I felt he was blowing hot air and trying to snow a kid who knew better. Anyway. Back to the topic at hand. I am quite sure that no one is proposing ALL the trackage on these modules must be 30" radius. Or whatever. Only the "main line", through which the cars must be distributed. As I mentioned a couple of posts ago, one guy wants to have 12" radius on his module. Since the "main" doesn't go through it, I don't see a problem. Ed
Right. It depends on how the through route is defined.
I think "through route" or similar is a better name for use on industry modules. The term "main track" is already defined by RR rules NORAC 10th ed. "MAIN TRACK: A track designated by Timetable upon which train movements are
authorized by ABS, DCS, or interlocking rules".
I worked the job that switched the big Sears near Olympic & Soto.
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Post by Baikal on Mar 24, 2024 18:08:56 GMT -8
If 42" curves are still a compromise from prototypical mainline curves (not sure what Free-mo means), what inch curves would you need to use to stay completely prototypical?
As broad as possible considering costs & benefits of various possible alignments- real estate, development, operating & maint costs, train speed, time savings, train handling, etc. Depends on what's around the R.O.W. that the RR has to deal with.
Like designing model railroad curves but moreso.
Use Google Earth "show ruler" to find the approx radius of any curve.
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Post by bncascadegreen on Mar 24, 2024 18:09:07 GMT -8
When I planned my layout I made the radius as big as I could. So I would not get over hang on “minimum”. Radi. So I went with 36. Turnouts 8 and 10.
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Post by edwardsutorik on Mar 24, 2024 19:04:36 GMT -8
My research has shown that 48" radius kinda sorta covers most prototype situations.
For example:
A DD40AX will work on 40.6", singly or coupled with same. That's prototype curves.
A DD40AX will work with 49.5" when coupled to a 50' boxcar. Again, prototype curves.
These are real UP numbers. These are NOT real UP numbers going 70 MPH out in the real world. They are, I believe, "going kinda slow and nobody being stupid".
For my two Free-mo curved modules, I went with 60", 'cause I thought it would be nice not to have "problems". I have not. Had "problems".
But we're talking about industrial trackage, here. No DD40AX's need apply.
Ed
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Post by bn7023 on Mar 24, 2024 23:13:07 GMT -8
What do you think is the radius of vertical curves?   |
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Post by jonklein611 on Mar 25, 2024 5:27:19 GMT -8
If 42" curves are still a compromise from prototypical mainline curves (not sure what Free-mo means), what inch curves would you need to use to stay completely prototypical? The prototype uses degrees of curvature per 100ft of length. A five degree curve, per John Armstrong would be limited to 50mph speeds, is equivalent to 158" radius. |
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Post by Baikal on Mar 25, 2024 6:02:23 GMT -8
If 42" curves are still a compromise from prototypical mainline curves (not sure what Free-mo means), what inch curves would you need to use to stay completely prototypical? The prototype uses degrees of curvature per 100ft of length. A five degree curve, per John Armstrong would be limited to 50mph speeds, is equivalent to 158" radius.
That's an over-simplified by Armstrong. Max speed calced by curvature depends on class of track, superelevation (cant), other. Prototype curvature can be and is measured in any units including meters as it's just a conversion factor between measurement systems. Using degrees per chord is confusing as model railroaders almost always have to convert it to ft/inches in order to visualize it.
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Post by jonklein611 on Mar 25, 2024 6:43:13 GMT -8
The prototype uses degrees of curvature per 100ft of length. A five degree curve, per John Armstrong would be limited to 50mph speeds, is equivalent to 158" radius.
That's an over-simplified by Armstrong. Max speed calced by curvature depends on class of track, superelevation (cant), other. Prototype curvature can be and is measured in any units including meters as it's just a conversion factor between measurement systems. Using degrees per chord is confusing as model railroaders almost always have to convert it to ft/inches in order to visualize it.
Agreed. It's from Armstrong's book, so it's a bit dated and I'm assuming he's talking about uncanted track. It still gives a rough frame of reference for what a "tighter" curve on a prototype railroad would be and how that translates to HO scale. 1-2 degrees would be the ideal case for mainline routes, 5-10 degrees (or sharper) may be required in mountain regions, and industrial stuff can get quite "tight" at 20-30 degrees. We model incredibly "tight" curves simply due to space constraints and the fact that 1:87 compresses things a bit. NRMA has some conversions listed here: www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-11_2018.03.03r.pdf |
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Post by Baikal on Mar 25, 2024 7:34:52 GMT -8
That's an over-simplified by Armstrong. Max speed calced by curvature depends on class of track, superelevation (cant), other. Prototype curvature can be and is measured in any units including meters as it's just a conversion factor between measurement systems. Using degrees per chord is confusing as model railroaders almost always have to convert it to ft/inches in order to visualize it.
Agreed. It's from Armstrong's book, so it's a bit dated and I'm assuming he's talking about uncanted track. It still gives a rough frame of reference for what a "tighter" curve on a prototype railroad would be and how that translates to HO scale. 1-2 degrees would be the ideal case for mainline routes, 5-10 degrees (or sharper) may be required in mountain regions, and industrial stuff can get quite "tight" at 20-30 degrees. We model incredibly "tight" curves simply due to space constraints and the fact that 1:87 compresses things a bit. NRMA has some conversions listed here: www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-11_2018.03.03r.pdf
Yeah. Here's an airphoto of UP's (former SP) reversing loop at West Colton. About 400 ft radius or 55" in HO, 30 percent larger than Free-mo's 42" minimum radius. It handles all equipment, but at slow speeds.
The Tehachapi Loop comes out to about 80" radius in HO, PRR's Horseshoe Curve is about 85". |
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