Scale and how much space does a half circle really take up?

ModelRailroadForums.com is a free Model Railroad Discussion Forum and photo gallery. We cover all scales and sizes of model railroads. Online since 2002, it's one of the oldest and largest model railroad forums on the web. Whether you're a master model railroader or just getting started, you'll find something of interest here.


Strasburgnut, Since you are not looping in the L corners, the diameter that the radius is based on is not the width of the layout (30"), but a point of that corner to a distance off the layout. Take a yard stick and extend it to somewhere in this diagonal line of the 90 deg corner. Put your finger on about 28" and pivot the stick in your hand, left and then right 45 degs. See where it comes out and adjust from that. Also, you don't have to wait until you are in the corner to start your curve. This will also give you greater radius. Where you do have a loop then 22" is about it for a 48" bench. One thing you could do if you have room is to mushroom the ends of the 48" sections. This will give you even larger radii.

I've read all kinds of recommendations for gigantic radii with total disregard to what a persons layout can accommodate. With HO, you should be able to handle most anything out there with a 24" radius and probably even 22" with good track. Yes, passenger cars look better with large radii, but if you want them and your existing curves of say 24" will run them ok, then get them...I do. I run several large articulated locos, several 6 axle diesels, and 3 passenger trains with 80 foot cars, and almost none of my curves are larger than 28". My articulates even go into many areas of 22".

Regardless of scale, good trackwork is the most important thing you will do on any layout. If you cut back on the quality of workmenship here, you will regret it quick. If you take your time and do it correctly, you will have many hours of running without a derail. I seldom have one and it has always been a mechanical failure of the car or something on the track.
 
Last edited by a moderator:
Rexhea,

Thanks for the advice. I have been able to understand that track work is important for any layout. Thanks for clarifying what I can run on what radius. This is going to be a lot of fun!
 


I am an N scaler and was a complete beginner at the start of the year, with an almost-complete (hah!) layout now. I have been journalling my progress in a thread and if you are interested you can read about all the mistakes I made and successes I had, as well as lots of great advice and encouragement from other members, at https://modelrailroadforums.com/forum/index.php?threads/a-beginners-journey-pt-2.38104/

On a couple of specific topics:

1. Track does not need to be perfect, but it does need to be good, i.e. better than some of my initial attempts. I ended up re-laying a couple of problematic areas where my gaps were too large. I used flextrack for most of the layout, except for the tightest mainline curve (12" radius) and some very tight curves in my yard (9"). I found that working with flextrack for long curves tried my patience, but was worth it in the end. There are lots of videos about laying flextrack that are worth watching.

Also there are lots of preferences about how to cut flextrack. I eventually settled on a Xuron flush cutter, well worth the cost, with jeweler's files for cleaning up burrs. I like it because I can readily make cuts either with the track in place or on the bench.

2. With those radii I am running small and medium sized freight cars, the longest being 60ft, and 85ft passenger cars without problems. My steam locos are both Pacifics and they run great too. However I tried running a Pennsylvania T1 articulated loco (from Broadway Limited) and found two things: i) it was sensitive to every slight imperfection of track, in part I think because there is no weight at all on the front bogie, which tended to jump the tracks; and ii) I felt it looked goofy on the 12" radius curves. I ended up returning it and getting a Pennsylvania K4 (Bachmann) instead, which looks almost as cool and runs perfectly.

3. I don't know if anybody already said this, but don't get hung up on period or location if that's not your thing. Some people's layouts are impressively true to a specific prototype, others are more casual. Do whatever gives you more fun. I am in the latter camp: my layout is broadly based on the B&O in the early 1950s so all the buildings and vehicles and almost all of the rolling stock conform to that. But I do get a regular "visitor" from the Penny in the form of my K4 with a rake of coaches. Next year I might also see a visit from the Atlantic Coast Line, just because I like the livery so much.

4. And to answer one of your first questions, Yes, there is a lot more availability in HO than N, but I have found plenty to satisfy me in N scale. However, if you plan on being strict about running one specific railroad, take the time to research locomotive availability. Some lines have very limited choices. From what I have seen, Pennsylvania or Union Pacific are good choices in that regard.

Hope that helps!
 
Not sure if anyone has brought this up, but, don't forget, you need aisle space that you have to figure with your benchwork and if you plan to walk all around it, it's up against a wall, or in a corner...or whatever. This must be in the equation.. It's all simple logic; widths, heights, curves, grades.. If you can't walk around it, then don't make it so deep that you can't easily reach across it to build something, repair, or rescue a stalled train.. Think over every aspect that will make or break a logical and satisfying situation before you jump in..Go slow and don't over purchase or bite off more than you can chew..Real trains don't go in a circle (except trolley lines and subways).. Nothing wrong with a point to point design where you have a wye, loop, or turntable at on or both ends and a passing siding midway where trains can go around one another..This set up causes you to operate realistically, whereas a circular design (continual/roundy-round) is more for just watching them roll...Which do you want ? One very good locomotive and some rolling stock is better than a 'train set' which usually has a cheaper loco and cars.. If you go N, then Atlas 55 code rail is the ticket..In HO go 83 or lower code rail..100 code rail scales out taller than the tallest 1:1 scale rail..But, if you buy old equipment, much of it have wheel flanges that are too deep for anything but 100 code rail an will bottom out on 83 or lower code rail..
 
Last edited:


StrasburgNut said:
I read that 13" radius is considered conventional in N scale.
Click to expand...
Always go with the largest radii possible.
I consider 13 to be kinda tight...

Use flex track. ME is best, Atlas has iffy quality turnouts.
If you use sectional track instead, make sure to use Kato!
 
Jacob Z said:
Why Atlas over Peco code 55? How are Atlas frogs wired? I couldn't find any information on that.
Click to expand...
Atlas track looks more "American" with it's smaller spikes.

Atlas C55 have little eyelets you can solder to. They stick out to the side, adjacent to the frog.

Peco turnouts are better quality then Atlas for sure.
 
Michael B said:
Atlas track looks more "American" with it's smaller spikes.

Atlas C55 have little eyelets you can solder to. They stick out to the side, adjacent to the frog.

Peco turnouts are better quality then Atlas for sure.
Click to expand...

Thank you. That's a remarkable level of detail that I was completely unaware of.

I see the little eyelets. I don't how to easy it is to conceal wiring that way? I soldered feeders to the bottom of joiners, which is a massive pain to install but makes them entirely invisible once the ballast goes down.
 
I'm going to elaborate a bit on UP2CSX's posts #14 and #16 above ^^^. I'm building myself in N-scale to a well known international standard known as "Free-mo," (originally conceived in HO) and in the case of the N-scale version it's known as "Free-moN." It's a modular system, and, except for the end-plates which join one module to the next, it's quite a loose standard generally--quite free form as design possibilities go. The end-plates are more tightly controlled, so that the modules can be easily connected at train shows and meets, etc.

I suggest searching on "Free-moN" at Youtube to see it in action. Most of the curves you'll see there are much wider than 22", but that's what flexibility is for.

The minimum radius for mainlines in Free-moN is 22," and I can tell you for a fact, because I've seen it over and over again, that 22" minimum is completely adequate to run very, very long trains, in particular those consisting of 89' flatcars and auto-racks. Trains of 30, 40, 50, 60 cars and if the track work is smooth, even those long trains will run very well indeed.

Smooth trackwork is one big key, regardless of scale, and I personally go with flex-track every time, as do most of the rest in these groups. Many will also build their own switches using "Fast Tracks" tools and jigs. In this area, a #10 switch* is a common standard at the ends of sidings. Smooth running stuff if done with care.

[* a #15 switch is actually used in real life, at least on the prototype I follow (the D&RGW), and it's rated for 30mph on the diverging route. The difference between the two? Just one single degree anyway. 😜]

I'm not posting any direct links, but just some search guidelines. Because searching and learning is all part of the fun...innit? 🧐:p:cool:

Enjoy your own journey.
 
Last edited:
One very important thing to note...because if you don't you WILL end up being frustrated with derailments unless you run very large curves or at very slow speeds: Regarding "Reverse curves," (aka curves which turn to one side, but which then change to the other direction--a left turn into a right turn and vice versa--at a MINIMUM in N-scale and HO too, always remember to connect the two curves with a straight section in between, unless it's very slow speed industrial/switching track. And even then, I would avoid it.

The length of the straight section should be equal to or greater than the length of the longest cars you intend to run, so with an N-scale 89' flatcar it would be curve, straight, curve in the opposite direction...and the length of the straight should be at least 6 3/4". Even longer is better if you have the space. This would apply to Superliners too, which are just a bit shorter than the long flatcars. I mention this because you are considering using sectional or connectable pieces of track (EZ track), rather than flex track, and if you do, ALWAYS add that straight section. A longer straight is even better, but when you are planning a layout don't forget this rule.

If you want to take your work to a higher level still, I suggest you use what are, in the real-world known as [mathematical] "spirals" and not just a straight section between reverse curves. I won't go into it here except to say "search on the subject." The math itself can get complicated, so don't bother (more on that follows).

Spirals look REALLY good when used correctly...and they should because the prototypes lay real mainline track with spirals, particularly higher speed track. But they do take up more space.

If you want more on the subject of spirals, you might start with Youtube also: It's quite common--in fact it's probably most common--to bypass all the mathematics (of spirals) and just use a piece of bent stick-wood to lay them out. Known as the "bent stripwood method." Many videos about track work, particularly when using flex-track will show you more. The gist of it is you fix one end of a piece of stripwood at the end of the straight, and you fix the other end to the radius you want...and the wood itself bends naturally. Then you just draw along the wood (without touching it or bending it) as a guide to plot your (flex-track) centerlines.

You can also do this--just once--onto a piece of heavy cardboard or artists mat board and cut along the line yourself to make a template. Voila! You now have created a spiral you can use everywhere on your layout...and you can put your pen or pencil right along the line when you lay your tracklines down.
 
Last edited:
You must log in or register to reply here.




Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here)

Back
Top