wjstix One of the more interesting presentations I ever attended was given by a university professor maybe 20+ years ago at a regional NMRA convention. One of the things he talked about was how people forget that Mallets were designed as a way to get big engines around curves. He had grown up in the coal country in West Virginia and said it was amazing how tight a curve some of those big engines could go around, with a lot of overhang.
One of the more interesting presentations I ever attended was given by a university professor maybe 20+ years ago at a regional NMRA convention. One of the things he talked about was how people forget that Mallets were designed as a way to get big engines around curves. He had grown up in the coal country in West Virginia and said it was amazing how tight a curve some of those big engines could go around, with a lot of overhang.
The 3 foot narrow gauge Uintah Railway on the Colorado/Utah border had 66 degree curves (91.8 ft radius - 12.65 inch HO) and ran 2-6-6-2T mallets. Grades were as steep as 7.5%. Must have been awesome to see them in action.
Seems like the best advice is if you're space limited, do what you have to do, and choose appropriate era and equipment.
Ray
BobVegas I want to take this 8X12 O gauge and make it a 4X8 or 5X8 HO scale, can it be done? Here is the link; http://ctt.trains.com/how-to/track-plan-database/2014/10/big-steam-in-the-coal-fields Rob
I want to take this 8X12 O gauge and make it a 4X8 or 5X8 HO scale, can it be done?
Here is the link; http://ctt.trains.com/how-to/track-plan-database/2014/10/big-steam-in-the-coal-fields
Rob
NO!
SouthPenn HO stands for Half O, so it would be 4 X 6. Good to go.
Yeah but... Lionel locomotives and rolling stock are designed to run on WAY tighter curves than HO stuff is. The Lionel plan (did you miss the fact that he said Lionel?) he's working from could have curves as tight as 27" DIAMETER (that's what O-27 means). Almost NO HO stuff will run on half of that.
Here's an example of an 8X12 Lionel plan I found online. The inside curves are 36" DIAMETER. That would come out as a 9" radius if you halved it to fit on a 4x6.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
BobVegasI want to take this 8X12 O gauge and make it a 4X8 or 5X8 HO scale, can it be done? Here is the link;http://ctt.trains.com/how-to/track-plan-database/2014/10/big-steam-in-the-coal-fields
Unfortunately, no. O-31 O Gauge curves as used in the linked design are 31” diameter to the outside of the track. Converting that to radius (measured to the center of the track) as used with scale layouts equals just under 15” radius (14.875”). Translating that to HO scale (48/87.1) yields an equivalent radius of just over 8” in HO, much too sharp for typical equipment.
Lionel Fastrack turnouts (track switches) are also quite sharp relative to typical HO scale turnouts.
As others have noted, O Gauge trains are engineered to go around these sharp curves by making compromises to scale dimensions and appearance.
For all these reasons, HO scale will likely not be as space-saving as you hope compared to O Gauge, and certainly not half the size for a similar layout versus O Gauge layouts designed with tighter O-27, O-31, or O-36 curves.
To look at it the other way around, HO scale 15” radius curves that are considered very sharp would be about equal to 55” diameter in O Gauge, so a little larger than O-54. 18” radius would be about equal to 66” diameter in O Gauge (between O-54 and O-72).
The key issue is the difference in the way most scale trains are engineered versus many O Gauge models.
Layout Design GalleryLayout Design Special Interest Group
Hello all,
RA1Will it help if I ease into the curve with 18 inch radius track on each end and only use 15 inch radius in the middle of the curve(?)
It depends...by putting a segment in the middle of the curve this changes the angle of the ends from a true 180º to a greater or lesser angle. If you are trying to replicate a true half circle (180º) this won't work unless you tweak the ends.
On my 4'x8' tabletop pike I use what I refer to as asymmetrical curves, be it 15-inch to 18-inch or 18-inch to 22-inch radii sectional track.
Sectional track is divided into segments of a circle. There are 12 segments in a 15-inch radius circle, and 12 segments in an 18-inch radius circle. In a 22-inch circle there are 16 segments.
I don't put a different radii in the middle of half circle. Rather, I put two quarters of the circles together.
With 15- to 18-inch I use three of each. To make a smooth transition between the different radii I put a short section of straight track between the two quarter circles; typically 1- to 2-inches.
Making an asymmetrical curve of 18- and 22-inch sectional pieces I uses three 18-inch sections to four pieces of 22-inch radii. Again I use a short section of straight track between the two quarter curves; 1- to 3-inches.
The purpose of the short sections between the quarter curves is to allow the cars to transition from one radii to the other without abrupt movements, possibly causing derailments.
Yes, you can combine different pieces of sectional track. Just remember that each abrupt transition is a possibility for derailment.
If you really need non-standard curves that sectional track can't provide consider comercially available flex track, or my tip on DIY flex track:
http://cs.trains.com/mrr/f/11/t/256138.aspx
(Highligh the link and then Right Click to open link.)
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
jjdamnit With 15- to 18-inch I use three of each. To make a smooth transition between the different radii I put a short section of straight track between the two quarter circles; typically 1- to 2-inches.
Honestly, I fail to understand the logic of this approach. To make a smoother transition between the straight track and the 15" curve, you put in a section of an 18" curve. That part is easy to understand; your train goes from straight into an 18" turn and then a 15" turn. Why would you then put a straight between the 18" and 15" curves? It gives you a straight-18"-straight-15" transition, containing the straight-15" transition you wanted to avoid in the first place.
jjdamnitWith 15- to 18-inch I use three of each. To make a smooth transition between the different radii I put a short section of straight track between the two quarter circles; typically 1- to 2-inches. Making an asymmetrical curve of 18- and 22-inch sectional pieces I uses three 18-inch sections to four pieces of 22-inch radii. Again I use a short section of straight track between the two quarter curves; 1- to 3-inches. The purpose of the short sections between the quarter curves is to allow the cars to transition from one radii to the other without abrupt movements, possibly causing derailments.
The movements will be more abrupt with the straight sections in there than having one curve leading into another directly (assuming these are in the same direction and it's not an s-curve).
In any case, this would be handled more smoothly (and more simply) with flextrack.
See also the recent posts by the Original Poster on another thread:
http://cs.trains.com/mrr/f/11/t/256330.aspx
One thing you could try, is looking at Kato HO Unitrack. It's sharpest curves are 16-7/8"R and 19-1/4"R. Should pretty much fit the same space as 15"-18"R curves, but a little more gradual.
Thanks I will check it out
posted in the wrong thread. move along, nothing to see here
Henry
COB Potomac & Northern
Shenandoah Valley
cuyamaThe movements will be more abrupt with the straight sections in there than having one curve leading into another directly (assuming these are in the same direction and it's not an s-curve).
I defer to my signature...
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry."
jjdamnit"Uhh...I didn’t know it was 'impossible' I just made it work...sorry."
Nobody said it was impossible, just that it wasn't a good idea. The fact it didn't blow up doesn't mean it "worked" as you describe it.
Because the straight sections are much shorter than a car length, they are not going to cause the normal transition issues. All you have done is created an irregular curve of a larger effective radius than you would have had normally.
I'd expect it probably looks funny because of the short sections of straight track interrupting the flowing curves typical of a real railroad. You'd have been better off making a smooth curve with real easements out of flex track using the same real estate.
I don't think you created a problem with what you've done, but you haven't created some new technique worthy of passing on as advice to others either.
carl425I don't think you created a problem with what you've done, but you haven't created some new technique worthy of passing on as advice to others either.
Isn't that for other modelers to decide?
EM-1 I can't look the date up right now, I have a 50+ year collection of MR and RMC in boxes in the attic, but I remember the issue was probably between 1961 and 1965. It was several pages long, with a number of pictures, so it probably was not in the Bull Session, which usually was a single page column.
I can't look the date up right now, I have a 50+ year collection of MR and RMC in boxes in the attic, but I remember the issue was probably between 1961 and 1965. It was several pages long, with a number of pictures, so it probably was not in the Bull Session, which usually was a single page column.
I don't have the issue handy, but I believe it ran in 1964 or 1965, possibly 1966. I think Bill Rau was the visitor. While he wrote the Bull Session column, this was not one of his columns but a regular article written by the owner of the layout (to which Rau added his remarks on the operating session), and included a photo of the layout, which indeed was on a bare sheet of plywood with no scenery and an oversized (Lionel?) station in one of the few spots not covered with track. There was a track plan. The larger engines resided on sidings connected to the outer loop. The layout was full of cars and engines, and did have some unconnected track sections. The owner also liked the look of his unpainted brass engines. He used a number of Docksides to switch his yards. I don't recall mention of any ten- or twelve-coupled engines, which would not have fared well on those curves. Despite extreme overhang two long articulated engines were able to pass each other in opposite directions on adjacent loops.
There was an editor's note that No. 4 turnouts had a much larger radius than 18 inches, and so the articulateds would not have a problem with them. (In N scale, for instance, an Atlas "standard" turnout is 19-inch radius, which corresponds to 35-inch radius in HO, while a 9-3/4-inch radius curve corresponds to 18-inch radius in HO.)
Keep in mind that O scale Lionel at least the stuff I have has truck mounted coupler which is very unprototypical but allows for tight curves. Good HO equipment has body mounted knuckle couplers that require larger curves. You can find some truck mpunted knuckles (Model Power now part of MRC makes some) that might be okay on 15" curves
Joe Staten Island West
A small corner goes well in n scale. Match your rolling stock to your layout, the tighter your radius, the shorter rolling stock you should use.
My n scale layout (40"x88)"has 15 and 16 inch radius, all laid in using flex track, and it handles Atlas 60' 4 wheel truck passenger cars very well, three locos, two GP-40 4 wheel trucks and a RS-3 switcher. All with body mounted couplers
In HO those radii would be nearly double that of n scale.
markpierce EM-1 I remember an article by one of MR's editors from sometime in the early 60s. He got an invite for a 4'X6' layout operating session. He started the report stating what his initial oppinion was, especially when he found out the layout had 15", 18", and 22" loops. He reported that after several hours, he had totaly forgotten the small radius curves, 5 or 6 car trains pulled by an Akane Yellowstone among other road engines, and an almost total lack of scenery. It was an operational joy. Until you can identify the specific month/year/magazine, I'll continue to believe your memory came from a dream.
EM-1 I remember an article by one of MR's editors from sometime in the early 60s. He got an invite for a 4'X6' layout operating session. He started the report stating what his initial oppinion was, especially when he found out the layout had 15", 18", and 22" loops. He reported that after several hours, he had totaly forgotten the small radius curves, 5 or 6 car trains pulled by an Akane Yellowstone among other road engines, and an almost total lack of scenery. It was an operational joy.
I remember an article by one of MR's editors from sometime in the early 60s. He got an invite for a 4'X6' layout operating session. He started the report stating what his initial oppinion was, especially when he found out the layout had 15", 18", and 22" loops.
He reported that after several hours, he had totaly forgotten the small radius curves, 5 or 6 car trains pulled by an Akane Yellowstone among other road engines, and an almost total lack of scenery. It was an operational joy.
Until you can identify the specific month/year/magazine, I'll continue to believe your memory came from a dream.
One of my other favorites from the era was an article about a 36" x 36" HO layout - an oval with 2 spurs, using 15" radius. The baseboard was a "tray" so scenery didn't have to be fastened down. The whole idea was changing theme, era, and operation depending on your whim of the day. Featured in June 1962 MR as a "Changeable Model Railroad" or similar.
Westcott was all about encocuraging the armchair modelers of his day to get up and actually build a layout. That was the reasoning behind the popular MR Project Layouts of the day. Lance Mindheim's "No Skills, No Problem" shelf layout and Carl Endt's micro layouts are more modern versions of the "get out of your chair and DO some model railroading".
Back to the OP. 15" radius works fine with 40ft cars and switchers (they can generally go down to 12"). F-7s, GPs, and 50ft cars will require more care and tuning of track and rolling stock to be derailment-free on 15". HO model Shays do struggle with 15" radius curves - it depends on how much extendability/compressibility is built into the line shafts.
Fred W
....modeling foggy coastal Oregon in HO and HOn3, where it's always 1900....
fwright Back to the OP. 15" radius works fine with 40ft cars and switchers (they can generally go down to 12"). F-7s, GPs, and 50ft cars will require more care and tuning of track and rolling stock to be derailment-free on 15". HO model Shays do struggle with 15" radius curves - it depends on how much extendability/compressibility is built into the line shafts. Fred W ....modeling foggy coastal Oregon in HO and HOn3, where it's always 1900....
I think the OP is long gone .... this thread was started in 2009 and he only made 3 posts !!!
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Another zombied thread raised from the dead.
Rio Grande. The Action Road - Focus 1977-1983