Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Smallest radius for HO scale?

144929 views
86 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    November 2011
  • 343 posts
Smallest radius for HO scale?
Posted by SUX V R40 Rider on Friday, December 2, 2011 10:32 AM

What is the smallest or tightest radius possible or used in HO scale? I am asking because as I am new to this hobby I am trying to figure out the amount of space I have in my home for a layout. I need to determine which will be best, HO or N scale.

For those of you who may ask why because you already know I am currenlty building an HO scale layout. The layout I am currently building is being done in HO scale for one reason. It is the only current train set I have. It will also be portable and donated to be put on public display once it is finished.

It is after this project that I need to figure out what scale to go with. I will provide my space dimensions later today.

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Friday, December 2, 2011 10:54 AM

Most HO scale locomotives except some of the newer ones, are made to operate on a minimum radius of 18 inches, depending on the manufacturer.  Cheaper models are usually designed for 18 inch radius operation because that's what comes in a train set, but more prototypical models require 22 inch or larger.

  • Member since
    May 2007
  • From: North Myrtle Beach, SC
  • 995 posts
Posted by Beach Bill on Friday, December 2, 2011 11:59 AM

I believe that in an earlier post you stated that your train set contained an AHM/IHC SD40-2.   Those six-wheel trucks and the size of the locomotive restrict your minimum.   I be pretty confident that locomotive would require a minimum radius of 18".    Code 83 track or larger would also be suggested.

Bill

With reasonable men, I will reason; with humane men I will plead; but to tyrants I will give no quarter, nor waste arguments where they will certainly be lost. William Lloyd Garrison
  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,386 posts
Posted by MisterBeasley on Friday, December 2, 2011 12:41 PM

For space reasons, I have a lot of 18-inch radius curves on my layout.  I run Transition Era and earlier equipment, mostly.  I don't run large steamers or long passenger cars.  Everything works.

If I stray just the least bit below 18 inches, though, I have a number of passenger cars which just won't make it.  This happened by accident, and I had to rip up a curve to fix it.

If you are running modern era or long passenger trains from any time frame, though, you will find that a lot of stuff won't work on those curves.  And, no matter what you're running or what time frame you're running it in, it will look better on bigger curves.  (With exceptions, of course, for trolleys and mining trains, which actually benefit from tight curves.

It takes an iron man to play with a toy iron horse. 

  • Member since
    November 2011
  • 343 posts
Posted by SUX V R40 Rider on Friday, December 2, 2011 1:01 PM

Bottom line nothing less than 18" radius and it is possible some cars will not work on it, depending on length?

Once I post the dimensions of the space I have to work with I'll ask what scale you would recommend.

Remember the set I am building will likely not be kept by me. That set is really not a consideration in deciding this.

  • Member since
    September 2004
  • From: Germany
  • 1,951 posts
Posted by wedudler on Friday, December 2, 2011 2:13 PM

You can squeeze some engines to an radius under 9'' like I did with my Pizza layout.

I've even widened there the gauge!

But for my Westport Terminal RR I've about 2' as minimum. With H0n3 you can go down to 15'' without problems.

Wolfgang

Pueblo & Salt Lake RR

Come to us http://www.westportterminal.de          my videos        my blog

  • Member since
    December 2001
  • From: Northern CA Bay Area
  • 4,387 posts
Posted by cuyama on Friday, December 2, 2011 6:05 PM

SUX V R40 Rider
What is the smallest or tightest radius possible or used in HO scale? 

Although I recognize that it's a frustrating answer, it depends.

What era are you modeling? What kind of equipment? Passenger trains? Auto carriers?

What space do you have?

For full-length passenger cars and modern longer cars and locomotives, the 18 inch radius figure folks bandy about will probably not be adequate in HO.

Byron

  • Member since
    September 2004
  • From: Dearborn Station
  • 24,095 posts
Posted by richhotrain on Friday, December 2, 2011 6:19 PM

SUX V R40 Rider

What is the smallest or tightest radius possible or used in HO scale? I am asking because as I am new to this hobby I am trying to figure out the amount of space I have in my home for a layout. I need to determine which will be best, HO or N scale.

If you have to ask, then go N scale.

That's not meant to be a smart aleck answer. If you are forced to restrict your curves to 18" radius or, perhaps, even tighter, then why not give yourself more options for a layout and for choices of locos, etc.

You do have one advantage, and that is the fact that you currently have very little HO scale equipment.  So, going from HO scale to N scale will not be a costly endeavor.

Rich

Alton Junction

  • Member since
    October 2004
  • From: Colorful Colorado
  • 8,639 posts
Posted by Texas Zepher on Friday, December 2, 2011 7:35 PM

I sucessfully did an HO layout with 15" radius curves so that it would fit on the top spot of a twin size bunk bed.   As the others have said it severly limits the equipment that you can run, and even if something runs it can still look ridiculous.

In N-scale I had an amazing layout in 2'x8' with 11" radius corners.  I ran full length passenger cars on it.

  • Member since
    May 2007
  • From: East Haddam, CT
  • 3,272 posts
Posted by CTValleyRR on Friday, December 2, 2011 7:45 PM

I agree -- you CAN put very tight curves on an HO layout.  I've bent flextrack into about a 6" radius... but that's because I was mad and trying to break it.

If you want your trains to run well, and, maybe more importantly, LOOK good, you want to go with the BIGGEST radius you can fit in, not the smallest.  My outer loop is 22-24", and a PROTO 2K ALCO PA with 80' heavyweight Bachmann Spectrum passenger cars will run on it just fine.

The inner loop is 18", and should I switch that train onto the inner loop, disaster awaits.

If space is a serious consideration, you'd be better served by N or Z scale.

Connecticut Valley Railroad A Branch of the New York, New Haven, and Hartford

"If you think you can do a thing or think you can't do a thing, you're right." -- Henry Ford

  • Member since
    February 2005
  • From: Southwest US
  • 12,914 posts
Posted by tomikawaTT on Friday, December 2, 2011 7:53 PM

The smallest radius for HO?

How about diameter of a silver dollar/2 plus 8.25mm.  That was the radius once run by a Varney Dockside 0-4-0T - a circle, with the inner "rail" a silver dollar.

In my case, 350mm, just under 14 inches.  All but one of the locos are teakettle tanks, most of the cars are about the size of a Minnesota ore jimmy.  Odd man out, a cosmetically modified Mantua 2-6-6-2.  OTOH, that loco's prototype was designed to round 90 foot radius curves...

Almost any locomotive will take an 18 inch radius - especially if the track is carefully laid with proper spiral easements.  Whether they will look good, bad or ugly, deponent saith not.  HOWEVER, there are freight and passenger cars that simply will not play nice on that radius.  I have several classes of passenger and freight cars which will bump end sills if coupled at prototypical distance from one another.

Everything I own will take a 610mm/24 inch radius without a hiccup - but I don't own any 85 foot streamliners with full-width diaphragms or 89 foot humonguboxes.

The only way to determine what radius YOUR rolling stock will take is to lay a test spiral and try it all out, singly and in every combination, no matter how unlikely.  Unlikely?  How about that aforementioned ore jimmy between two full-length Pullmans with body-mounted couplers...

Chuck (Modeling Central Japan in September, 1964)

 

  • Member since
    September 2007
  • From: Charlotte, NC
  • 6,099 posts
Posted by Phoebe Vet on Friday, December 2, 2011 8:56 PM

Most of my curves are between 26" and 34" radius but the original 4x8 which is embedded in the layout has 18" and 22" curves.  Some of my trains don't get along well with the 18s at all.  It's not a problem because I can bypass that part of the track.  On the other hand I have some 15" curves in the subway but the subway cars are very short.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    November 2011
  • 343 posts
Posted by SUX V R40 Rider on Friday, December 2, 2011 8:59 PM

The size of the space in my basement is that I can start with is: 8' x 12'. Part of that is used by permanently placed things like drain pipe/clean out, etc. These are things I do not want to block and would need access to just in case. So the space I can start with is more like 8' x 10'. Later on I may be able to move things around that take up space in the rest of this room of the basement. For now 8' x 10' is all I have to work with.

What do you suggest for a space this small? HO or N scale?

  • Member since
    December 2007
  • From: Southern Maryland
  • 66 posts
Posted by VunderBob on Friday, December 2, 2011 9:29 PM

You can get a very nice HO layout in an 8X10 or 12 space if you put shelves on the walls instead of an island in the middle of the room. Of course, same space would get you a veritable empire in N...

You need to evaluate:

-The actual room. Look long and hard at secondary uses as well as the obstacles you mentioned.

-The desired operating style of your layout (roundy-round display? switching? mainline ops?)

-Era. Older timeframes generally meant shorter cars and engines, and they work on sharper curves without issues.

-Your eyesight. HO is a lot more forgiving than N in that regard.

-Budget. HO used to be half the cost of N years ago purely because more was produced. These days, N is approaching HO in sales volume. The cost break for the larger scale is still there, but not nearly as great.

In the world of Bob the Rail Baron, I have a personal standard of 22" as an absolute minimum for a mainline radius, with 24" preferred. I will use 18" for a minimum on a spur in a heartbeat, because I like sharp curves on industrial trackage. Bear in mind that I am also targeting 1980ish equipment. If I was modeling Civil War to turn of the 20th Century, 18" would be generous for mainline curves. This also applies to narrow gauge.

I'm not trying to advocate one scale over the other, but my experience is HO. I can tell you right now that if I didn't have a minor fortune in rolling stock waiting for my next layout to be built, I'd be into N in a New York minute, bad eyes be durned.

I used to be clueless, but i've turned that around 360 degrees.

  • Member since
    November 2011
  • 343 posts
Posted by SUX V R40 Rider on Friday, December 2, 2011 11:29 PM

The era I am going to run is form 1971 to today.

The over all inside dimensions of this large room that makes up the one half in the basement is: 12' wide x  over 35' long.

In the 8' x 10' space I was planning on a shelf style layout as 2 of the walls are the outside basement walls. Where the layout can go is at one end of the room.

 What takes up the rest of the space in this room are bicycle storage, building material storage, work work space and electric table top tool storage.

Of all of this the only part that is NOT negotiable in terms of relocation is my bicycle storage. 3 bikes hang from hooks with the tools and other gear on a shelf unit or the floor under where the bikes hang from. Cycling is my first love, above all other "hobbies", but only during the spring and summer. During the cold months this is the only place the bicycles can be stored.

Across from where the bikes are stored is material storage. I have lumber, paneling, metal and insulation materials organized and stacked on the floor or leaning against the wall. The material storage runs along part of the length of the 35' long span.

In front of that near the material storage and next to the bicycle storage area, is the area i use as a large work space. I need at least a 4' x 8' space to work with.

Next to that, now at the end of the room where the 8' x 10' space is for a train layout, is where I store my table top electric tools. Router table with attached router, small table saw, miter saw, etc. They will have to be moved when I build a layout there. I think I have just enough space to find for all of it in my shop on the other side of the basement. The other side of the basement, in the same room as my shop is also where the utility infrastructure is located so no room at all for a train layout or for working on large projects.

I would love to relocate the metal and building materials stored in this room to somewhere else. Some of it I would be able to get rid of as scrap. Also if I take up the work space I use for projects for a train layout I would only be able to do such projects outside on the patio, during warm months because this room would then be the train room/bicycle storage facility. I would love to use the entire length of this room for a train layout.

If anyone has ideas for material storage I'm open to suggestions. Before you recommend anything I do have a detached, single car garage and could store some of the materials in the rafters. I am open to other ideas as well.

  • Member since
    November 2006
  • From: huizen, 15 miles from Amsterdam
  • 1,484 posts
Posted by Paulus Jas on Saturday, December 3, 2011 2:23 AM

hi,

since you like to build a rather modern layout you have to deal with modern long freightcars. This means the use of 24"+ radii and #6 turnouts. In HO you will find it nearly impossible to find a good trackplan with lots of operating possibilities. The HOG could be build in your space.

If you think this is to small, N scale would be the best bet.  IMHO the spurs are to short and industries to small for a modern layout, it would be more appropriate for a 50's or 60's plan. The length of cars and engines were 60 feet or less in those days.

To give an idea about the possibilities in N-scale:

Per item N-scale prizes are not that different from HO prizes. Keep in mind you have easily 3 times as much items on a N-scale layout. The N-scale plan has 45 turnouts, the HO scale HOG just 13.

Smile
Paul

  • Member since
    September 2004
  • From: Dearborn Station
  • 24,095 posts
Posted by richhotrain on Saturday, December 3, 2011 4:11 AM

Let's face the issue head on and ask the critical question.

How willing are you to consider N scale?

Or, asked another way, are you more inclined to stick with HO scale?

I would answer that question first if I were you, so that we can focus in on your space and help you design your layout.

So, what's it going to be: N scale or HO scale?

Rich

Alton Junction

  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Saturday, December 3, 2011 5:16 AM

The OP seems to be still undecided, whether to stay with HO scale, or to switch to N scale.

Just a few words on N scale. It has come a long way on those 50 + years since its introduction. In terms of detail and quality, it is on par with HO scale. It has retained its biggest advantage - size, and it has also kept its biggest drawback - size. All these tiny details are hardly visible from a "normal" viewing distance. You need to stick your nose quite close to your loco to enjoy the detail. I use pictures I take to endulge into the detail of my steamer.

off course, there are ways to solve the issue. Just build your layout high enough zo bring it up as close to eye level as possible. This may limit the depth of it, but that´s no issue for me.

The choice of supplies is still somewhat limited, especially when you want to enjoy steam on your layout. There are the ubiquitous Big Boys, Challengers and other Articulateds, but the choice of smaller steamers is limited. Bachmann has just released a nice 2-10-2, which might even entice me to start modeling US prototype one day. Bachmann´s 4-6-0 is also quite nice.

DCC is no problem anymore, but sound still is. There are sound locos available, but don´t expect too much out of those tiny speakers.

Summing it up, N scale is a viable choice! If you leaf through this forum, you´ll see a selection of beautifully crafted, atmospheric layouts.

  • Member since
    September 2004
  • From: Germany
  • 1,951 posts
Posted by wedudler on Saturday, December 3, 2011 6:22 AM

And don't forget H0n3. With narrow gauge you have short trains, sharp curves steep grades. Prototypically!

15'' radius is no problem. And - it's still H0. I like it. Smile

You can get RTR sound engines from Blackstone.

Wolfgang

Pueblo & Salt Lake RR

Come to us http://www.westportterminal.de          my videos        my blog

  • Member since
    June 2003
  • From: Culpeper, Va
  • 8,201 posts
Posted by IRONROOSTER on Saturday, December 3, 2011 6:48 AM

The real question is how small can the trains be and still be satisfying to you?  That's the size to go with.

If you pick N, build the layout very high, 55 - 60 inches depending on your height.  It will look a lot better just below eye level. 

Enjoy

Paul

If you're having fun, you're doing it the right way.
  • Member since
    November 2011
  • 343 posts
Posted by SUX V R40 Rider on Saturday, December 3, 2011 7:05 AM

wedudler

And don't forget H0n3. With narrow gauge you have short trains, sharp curves steep grades. Prototypically!

15'' radius is no problem. And - it's still H0. I like it. Smile

You can get RTR sound engines from Blackstone.

Wolfgang

Please explain the difference between HO and HOn3. Is the body size the same but the wheel/truck size and spacing different? Or is HOn3 between N and HO scale? Also what about availability of choice of engines, cars, etc? Are as many engines found in HOn3 as with HO?

  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Saturday, December 3, 2011 9:00 AM

HOn3 resembles 3 ft. narrow gauge in HO scale. Locos and rolling stock are slightly smaller, but HO structures, vehicles, figures are the same.

HOn3 is really a niche market. Other than Blackstone, there are hardly any manufacturers around. Choice is limited, and what´s on the market ain´t no bargain.

  • Member since
    February 2009
  • 48 posts
Posted by JonMN on Saturday, December 3, 2011 9:22 AM

CTValleyRR

  I've bent flextrack into about a 6" radius... but that's because I was mad and trying to break it.

LOL

 

Jon

  • Member since
    December 2001
  • From: Northern CA Bay Area
  • 4,387 posts
Posted by cuyama on Saturday, December 3, 2011 10:19 AM

HOn3 doesn't really seem to fit the Original Poster's interest at all, IMHO. 3 foot gauge railroads disappeared for the most part by the 1930s and 1940s, thirty years before his desired time-frame. So the models are of older, smaller, quainter equipment.

I was not able to follow the Orignal Poster's description of his space very well, perhaps others did. Here's an example of an HO layout in 8X10, with solid walls around it. If the OP can use some of the surrounding space for aisles, more is possible within the 8X10 space itself. 

Here's another HO 8X10 layout example around-the-room with a duck-under, lift-out, or swing-gate. A little broader radius is possible (24" here vs. 22").

One could accomplish quite a bit more in N scale in the space, of course, Here's a modern N scale layout example using 13 inch minimum radius (equivalent to nearly 24" in HO). There is plenty of room still for aisles here, so obviously the radius could be broadened even more. 13" radius in N scale will handle just about all equipment, 15" should accommodate everything.

Byron

 

  • Member since
    November 2011
  • 343 posts
Posted by SUX V R40 Rider on Saturday, December 3, 2011 12:56 PM

I think I'll stay away form HOn3. With the examples of possible layouts in both HO an N it seems I can create a really good layout in an 8' x 10' in HO and an even better one in N. When I figure out when I can have even more space in the 35' length of the room my my basement I will have an even better HO or N layout.

For right now lets say I will stick with HO scale in the 8' x 10' space. As mentioned the era is from 1971 to the present. I will probably stick with 1971 to just before cabooses were no longer used, mid 1980's. Now to decide what type of train I want to start with in this layout. The layout I am building for the Hy-Vee train is not going to be used for this. I am wanting a new better quality train set. Let's start with brand. What is a good quality train set brand from 1971 to the mid 1980's that includes engine and cars?

BTW I have discovered, with the Hy-Vee layout and what trains I have seen, that I like themes. For example a military theme, or beer train theme that I could center around a brewery building, etc.

Thanks.

  • Member since
    May 2007
  • From: East Haddam, CT
  • 3,272 posts
Posted by CTValleyRR on Saturday, December 3, 2011 1:21 PM

Modern equipment and locos tend to be longer than transition era stuff (except the Big Boys and the other huge locos that were steam's last hurrah).  You will probably need at least 22" radii on your layout to run this stuff.

On the other hand, most of the "themed" sets that I've seen are designed to run on 18" curves, so you'll be ok if that's all you plan to run.

Connecticut Valley Railroad A Branch of the New York, New Haven, and Hartford

"If you think you can do a thing or think you can't do a thing, you're right." -- Henry Ford

  • Member since
    November 2011
  • 343 posts
Posted by SUX V R40 Rider on Saturday, December 3, 2011 2:24 PM

I am going to guess that what model railroaders run is personal choice, correct?

If that is correct is there anything wrong with running themed sets, with a continuous run of track connecting them together, leading to a round house and rail yard with maintenance shop where I can park the engines and cars when not in operation? When I do operate them I connect the engines to the appropriate cars, run it to the part of the layout that it goes with, based on the theme and enjoy.Though it may not be your preferance or "cup of tea", does anyone see a problem with this?

With a round house, does one have to have a turn table? Are round houses and turn tables even used after 1970? Or has their use dwindled since? If it has, what is used for full size modern applications? Is it more of a maintenance shop with track runs going in and out with out a turn table? If this is the modern application with full size please advise of the technical term.

  • Member since
    September 2007
  • From: Charlotte, NC
  • 6,099 posts
Posted by Phoebe Vet on Saturday, December 3, 2011 3:14 PM

It's your rail road you can do whatever you like.

There are a few turntables around, but most of them are gone.

Without a turntable there is no way to get into and out of a roundhouse, but there are engine houses and transfer tables that can do the job.  Most maint facilities today use switches to get in the various bays.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    November 2011
  • 343 posts
Posted by SUX V R40 Rider on Saturday, December 3, 2011 5:35 PM

The maint. bays and switches it is. I take it when an engine is just parked it sits on an open section of track next to the maint. bay? Or are they usually connected to the rest of the consist?

I think I will start my layout by building the maintenance bay with rail yard first in the section I currently have available to start with in my basement.

I know I can decide on shelf or bench work. I'm going with shelf because the basement floor is uneven in places.

I have looked and cannot find a modern looking HO scale diesel locomotive maintenance building. I'll also need one for the cars too. Can anyone provide a link for me?

  • Member since
    July 2006
  • From: Sorumsand, Norway
  • 3,417 posts
Posted by steinjr on Saturday, December 3, 2011 5:43 PM

http://www.kalmbachstore.com/12447.html

If you should develop a desire to understand how real railroads work and how they might be modeled:
http://www.kalmbachstore.com/12148.html

Smile,
Stein

 

 

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!