Model Railroading > What 42 radius Looks Like in HO with Full-Length Cars

Often someone asks what the minimum radius in HO is that looks good with full-length cars. Most of the cars here are the same length as modern autorack cars. Here are two photos from my layout of a 42 in. radius curve. I use spiral easements too. To me this would be the maximum I would use in HO for long rolling stock on visible curves. With curves not visible, for example, in a helix or hidden track, 30 in. radius is fine. The train is for now a mockup with the cars to be painted or stripped and painted Wabash with some kits not yet completed.  (The roadbed was made from strips of moulding glued together vertically. This is a main and siding.)

I even made a compound curve at the end of a peninsula with part of the curve hidden. The visible part is 42 in. radius with an easement, and the part of that same curve not visible, 30 in. radius. That allowed me to use the 42 in. radius to the best effect while saving space at the end of the peninsula. (I would never allow an entire turnback curve to be seen anyway, as I despise seeing a train do a 180.)

This is what I have often harped on in layout design with using “functional” (minimum radius for reliable operation) in hidden sections and "cosmetic" curves for visible curves. The idea was presented in an NMRA publication many years ago. This is something not always obvious to modelers in that they get hung up with using the largest radius possible on the entire layout, including hidden tracks when they could have some of the more visible curves at the max radius for realism. Hidden track doesn't necessarily have to be that in tunnels or behind backdrops but just where the trains and curves aren't that visible like that behind buildings, trees, or a section of the layout not normally viewed fully during operation.

For those of you curious about the makeup of the train: the train runs btw Toledo and Fort Wayne and then down my freelance Indianapolis Branch to Indy and vice versa. Cars which include RPO, baggage, coaches and sleepers are exchanged with mainline trains btw Detroit and St. Louis at Fort Wayne and run to Indy and return back to Toledo via Fort Wayne. The positioning of the cars facilitate switching at Fort Wayne. There is also a backup move btw a junction and the station at Fort Wayne, which makes operation even more interesting but very efficient. The line to Indy would facilitate the shortest and most direct RR btw Detroit and Indy and Toledo and Indy. A businessman can board a sleeper at Toledo and sleep all the way to St. Louis or Indy, depending on which sleeper he boards. The Indy sleeper would arrive at Indy in the wee hours and be parked at Indy Union Station. Both Nos. 12 and 13 would be night trains.

Victor A. Baird
http://www.erstwhilepublications.com
 



Edited 14 time(s). Last edit at 03/18/21 15:55 by wabash2800.

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Neat! That's why I model in N Scale!

Bill Deaver
Tehachapi, CA

Neat trackwork ... does the curve with the train have easments?

Thanks,

* JB *

GUYS....Many of the modelers are restricted by wifes who play a big part in how much space one has and a lot of devorse take place over being a railfan or a modeler....I have 32 and 36 inch curves on the main line and the heavy weights when going around the curves hang over as do the auto racks and pig flats. But thats part of model railroading.   42 inches is a great curve and I'm sure that many would love to be able to have such lck and be able to build curves like that....Good for you...

Some of you guys are missing Victors point. He's not saying 42 inch minimum. Obviously most of us can't run with all 42 inch curves, but having a few showcase curves in key spots goes a long way to improving the appearance of the layout and trains running on it. It also allows for good photo opportunities if that's your thing. 

42 inches looks great, but even that would be considered a sharp curve on the prototype!

I have 32" curves and I run only 40 ft cars for freight .  If you want passenger trains on less than 42" radius  run shorter passenger cars.



Edited 1 time(s). Last edit at 11/10/20 20:54 by tomstp.

BlackWidow Wrote:
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> 42 inches looks great, but even that would be
> considered a sharp curve on the prototype!

If I have done the math right, 42 inches is 304 foot 6 inches. That is an 18 degree 49 minute curve, sharper than the north end of the Fraser River bridge in New Westminster BC, the south end of the Steel Bridge in Portland, or the Coach Wye in Seattle. With 1 inch superelevation, the speed limit would be 17 mph. The usual maximum main line curvature, for example, through mountain areas, is 10 degrees (572.97 foot radius, which is 79 inch radius in HO (speed limit 24 mph with 1 inch superelevation). Consider that in HO, a No 8 turnout is luxurious and high speed, while in 1:1, it is a very sharp yard turnout. BN minimum yard turnout standard was No 9. Sometimes, artistic license is essential.

TAW

That was what I wrote. And I also bank the curves gradually entering and exiting the curves using the easement section as a marker.

Victor A. Baird
http://www.erstwhilepublications.com

prr4828 Wrote:
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> Neat trackwork ... does the curve with the train
> have easments?
>
> Thanks,
>
> * JB *

Agreed, but modeling is often an illusion. Using prototype radius curves larger than my example would be a waste of space when a 42 in. radius curve in this example will do the trick. Also, note that often turnouts in prototype photos look smaller than they really are, though they usually start out at a minimum of a No. 10. Here again, using prototype No. turnouts would be a waste of space of anything bigger than a No. 8 in HO. I have laid multiple crossovers as No. 8s connected together as a test with long passenger trains and haven't had a problem. And they still take up a lot of space.

Victor A. Baird
http://www.erstwhiepublications.com

BlackWidow Wrote:
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> 42 inches looks great, but even that would be
> considered a sharp curve on the prototype!



Edited 2 time(s). Last edit at 11/11/20 21:03 by wabash2800.

tomstp Wrote:
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> I have 32" curves and I run only 40 ft cars for
> freight .  If you want passenger trains on less
> than 43" radius  run shorter passenger cars.

Not everyone has that luxury... A lot of the layouts I see in GMR and other magazines are bigger than my entire house, and sometimes bigger than my entire property! :-D

My layout is 12x45 feet, and I had to take over most of the garage to get that kind of real estate.

I have a 36" minimum radius and I run primarily passenger trains with full-length cars made by some crappy manufacturer in Canada.

They look fine to me...

-Jason

 

rapidotrains Wrote:
-------------------------------------------------------
> tomstp Wrote:
> --------------------------------------------------
> -----
> > I have 32" curves and I run only 40 ft cars for
> > freight .  If you want passenger trains on
> less
> > than 43" radius  run shorter passenger cars.
>
> Not everyone has that luxury... A lot of the
> layouts I see in GMR and other magazines are
> bigger than my entire house, and sometimes bigger
> than my entire property! :-D
>
> My layout is 12x45 feet, and I had to take over
> most of the garage to get that kind of real
> estate.
>
> I have a 36" minimum radius and I run primarily
> passenger trains with full-length cars made by
> some crappy manufacturer in Canada.
>
> They look fine to me...
>
> -Jason
>
>
LOL  

Two qualifications on sharp curves with long cars:
a)   Works best at approximately eyeball height, and worst if you are looking down at the track.
b)   Really works if viewed from the inside of the curve.  From the outside [ as a looping curve at the end of a peninsula ], not so much.

SZ  -- 0 scale person

rapidotrains Wrote:
-------------------------------------------------------
> tomstp Wrote:
> --------------------------------------------------
> -----
> > I have 32" curves and I run only 40 ft cars for
> > freight .  If you want passenger trains on
> less
> > than 43" radius  run shorter passenger cars.
>
> Not everyone has that luxury... A lot of the
> layouts I see in GMR and other magazines are
> bigger than my entire house, and sometimes bigger
> than my entire property! :-D
>
> My layout is 12x45 feet, and I had to take over
> most of the garage to get that kind of real
> estate.
>
> I have a 36" minimum radius and I run primarily
> passenger trains with full-length cars made by
> some crappy manufacturer in Canada.
>
> They look fine to me...
>
> -Jason
>
>  

That was funny! I have 30” curves to fit my layout in a bedroom (my home office actually). Would I like bigger curves? Absolutely! But that won’t happen until the kids move out and I get the whole basement. Or buy a different house, again, without the kids. :)

That 42” curve sure looks great!

Nathan

Posted from iPhone

Max 36" mainline radius on my 13'x27' basement "empire" here too, and I thought that was _luxurious_ when I fit those in. Will have some 89' autoracks in my freight manifests, and Amtrak Superliners for the varnish - with the 261.com fleet occasionally running behind my 1:87 scale Kato Empire Builder.

MichiganRailfan Wrote:
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> Max 36" mainline radius on my 13'x27' basement
> "empire" here too, and I thought that was
> _luxurious_ when I fit those in. Will have some
> 89' autoracks in my freight manifests, and Amtrak
> Superliners for the varnish - with the 261.com
> fleet occasionally running behind my 1:87 scale
> Kato Empire Builder.

My basement layout space is about 15 x 33 feet with a minium radius is 32" for my basement layout, with some curves in the 36 to 46 inch range.  The actual layout width is 12.5 feet to avoid lift out a liftout bridge or duckunder.  Otherwise the minimum curve radius could have been substantially larger.  I plan run 89' TOFC and autoracks as well as passenger trains such as the Amtrak California Zephyr and Rio Grande Zephyr, as well as some one-off passenger trains like the San Francisco Zephyr (which did detour over the D&RGW) and late 60's California Zephyr.

Cheers,
Jim

Awesome passenger train consist behind that pacific!  It looks very railroad-like on 42' R.  Nice!!

On my upper level I have between 56 and 70 inch radiuses with easements along with one 36 inch radius in a tight spot that is in Yard Limits. I also broke the "rules" with NMRA standards for super-elevation with a maximum of .80 (NMRA is .40) and easements. The rise to .80 is 12 inches on tangent rail prior to easement - This prevents a climb out, especially with Walthers cars which go through a modification beforehand. After each curve was laid (This one was actually laid by a good friend) I carefully went back and fixed any dips in both the inside and outside rail. With extreme care, planning, and execution the track can be the showpiece for your equipment. Personally, I love super-elevated curves and seeing trains roar through them.

Laying your track should be done with patience and attention to detail. Irregardless of what train or power you use, it will not look or feel right if you're impatient and the quality is bad with all the lurching etc.

Here is the St. Petersburg section of Amtrak's southbound Floridian running around a hot SCL intermodal headed toward Tampa.



Edited 1 time(s). Last edit at 11/11/20 09:27 by RailThunder.

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Nice.  And an ex-NP dome following the SDP40F, the dome in phase 1 Amtrak.  No baggage on the Floridian?  Those super elevations look great.  Many of us can only dream of 56 and 70 radius curves.

I'm a fan of the phase 1 scheme and modeling a San Francisco Zephyr and those domes were used in the late 1970's after restrictions were lifted over Donner Pass in CA.

Cheers,
Jim

Wow!  I had to enlarge my Christmas tree layout from 4 x 8 to 7 x 9 to get 35 inch curves, which I thought would be perfect.  Most of my passenger equipment looks and runs ok on my 35 inch main line, but I do have some equipment that still needs broader curves.