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Curve Radius

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  • Member since
    February, 2002
  • From: Reading, PA
  • 22,408 posts
Posted by rrinker on Saturday, March 18, 2017 11:27 PM

ROBERT PETRICK

Following up on my previous post.

First: I'm typing this on my cell phone, so long complicated missives are a bit difficult.

Second: I model N scale, so any numbers bandied about need to be multiplied by 2 so that HOers can relate.

Third: the OP was about HO scale curves, but since the OPer seems to have dropped out and since Atlantic Central wanted to expand the thread to a broader discussion, I'll bite.

Fourth: specific acknowledgement that opinions may vary.

The absolute minimum radius on my layout is 18", and those occur mainly in the yards due to the Peco medium turnouts (estimated to be #6). Most of the curves are in the 24" to 30" range. Several are in the 36" to 48" range. A couple are in the 60" to 90" range. I have one long, broad curve that is 72" radius, but it runs exactly parallel with the fascia. So, do I get points for such a broad curve? Or, do I lose points because it follows the fascia?

My train room is 24' by 25' and the layout footprint is about 18' by 25'. I look at it as the world's largest diorama, with a few kenetic elements tossed in here and there for fun. My main design criteria was to create scenic vistas, and if spectators stand in certain locations around the layout and look in particular directions, they'd see the vistas I intended to create. I will do my best to try to make those scenes as un-boring as I can. Here is a sketch of the layout with the vantage points I wanted to include. There are two #4 viewpoints (Dang!)

Robert

 

 

 

Despite saying you have some relatively tight radius curves, you actually have, in that plan, implemented many of the ideas being mentioned. Most of your tighter curves, the exception being the two at the top of the right hand aisle, are viewed fromt he outside, not the inside - this helps dimish the appearance issues on tighter radius curves. It's not really possible to make EVERY curve viewable only from the outside, so there's nothing wrong there. That nice gentle curve to thr right of the middle aisle more than makes ip for it. And the sweeping curves through the river scene on the left - I'll bet that becomes your favorite place to photograph a train once all the scenery is done.

                                       --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by 7j43k on Sunday, March 19, 2017 12:40 AM

When I first saw Robert's layout, I really liked it.  It is NOT flamboyant.  And I do think it could use fine-tuning--like a couple of curves oddly connected by straights.  And I think I might add some crossovers on the double track.  And various versions of yards are missing.  But it REALLY feels comfortable to me.  I like that layout.

 

Ed

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  • From: Northern Virginia
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Posted by riogrande5761 on Sunday, March 19, 2017 8:14 AM

BMMECNYC

 

 
Lone Wolf and Santa Fe
If you know you are modeling an era with short locos and short cars then you could use 18 inch curves but if you can use bigger it is always better.

 

This is not really accurate.  Bigger is not always better.  You could put a 72" radius minimum in a 13ft wide room...

 

Yes, but taken in the spirit with which it was meant, I agree.  We need to talk like lawyers on this forum and word our posts very carefully to avoid the "yeah, but" replies.  So let me give this a try, "where possible, bigger is always better."?

Rio Grande.  The Action Road

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Posted by BMMECNYC on Sunday, March 19, 2017 8:46 AM

riogrande5761
 
BMMECNYC

 

 
Lone Wolf and Santa Fe
If you know you are modeling an era with short locos and short cars then you could use 18 inch curves but if you can use bigger it is always better.

 

This is not really accurate.  Bigger is not always better.  You could put a 72" radius minimum in a 13ft wide room...

 

 

 

Yes, but taken in the spirit with which it was meant, I agree.  We need to talk like lawyers on this forum and word our posts very carefully to avoid the "yeah, but" replies.  So let me give this a try, "where possible, bigger is always better."?

 

Still, no, not always.  The russians tried that with a 4-14-4 or something like that... didnt work out.

Bigger can be a huge waste of space for spur tracks (it is situational).   Having a your mainline minimum radius for every spur track is excessive.  You only need the minimum that the rolling stock that serves that industry/minimum that your locomotive doing the switching can handle reliably.  Anything over that is gravy.  But not necessarily better.   A broad radius is a space eater.  If you arent using big rollingstock or locomotives, why would you give up that space when you could use it elsewhere. 

You dont need curves that make a 85' passenger car look good when you are spotting a 36' or 40' car an industry with a cab end switcher.

riogrande5761
We need to talk like lawyers on this forum and word our posts very carefully to avoid the "yeah, but" replies.

We dont need to talk like lawyers, just avoid using inaccurate broad generalizations. 

Rule 108: In case of doubt or uncertainty, the safe course must be taken.
  • Member since
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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Sunday, March 19, 2017 9:17 AM

Well obviously industrial trackage need only be built to standards for the equipment that will operate there.

BUT, the trap of building a mainline to standards that are too restrictive, is that a lot of people in this hobby are always changing their mind about what, where, when and how to model.

OR, they simply don't know yet that they want 85' passenger cars or auto racks.........

Given the space, it makes perfect sense to build a mainline to handle the longest typical prototype equipment.....and even if you are modeling 1905, they had 80' passenger cars then..........

It will look better and run better.

Sheldon 

    

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  • From: Culpeper, Va
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Posted by IRONROOSTER on Sunday, March 19, 2017 9:24 AM

This reminds me of some old discussions on which scale is the best.  or Which era is the best.  or Which prototype road is the best.

There is no best and no universal rule of thumb.  Every layout we build and operate has compromises with faithfully modelling the prototype. Partly this is because we have limitations, but partly because somethings are just boring.  Do you really want to run a train at scale speed for a 20 mile stretch of track in the country with no stations or sidings (approx. 1200 ft in HO) and/or build the layout to support that? neither do I.  Do you accurately model the basement interior of every house on your layout? neither do I.

You figure out what you want to do and then how to best do it given your space, time, and money resources.  If that means running 80' passenger cars on 18" curves then that's what's right for you.  If you like to kick back and watch your 4-4-0 pull 36' boxcars around a 60" curve, then by all means do that.

BTW the best scale is not the one you're using.  You also have the wrong era.  And You need to pick a better prototype. Laugh

Paul

If you're having fun, you're doing it the right way.
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Posted by ROBERT PETRICK on Sunday, March 19, 2017 10:27 AM

7j43k

When I first saw Robert's layout, I really liked it.  It is NOT flamboyant . . . But it REALLY feels comfortable to me.

Ed 

Hey thanks, Ed.

You know, oddly enough, comfortable is exactly what I was shooting for. I never thought about flamboyant one way or another, but I kinda like the idea of being not.

I specifically wanted a double mainline throughout for long, continuous runs that allow trains to stretch their legs. I like trains to run; to pick up stuff here and deliver it over there, and over there is usually a long way away with lots of nothing in between. I have a very low trackage-to-scenery ratio.

The only crossover of the two mains is effected by the convergence of the east- and west approaches to the Littlefield bridge shown at the bottom of the sketch. The lack of convenient crossovers means (just like in real life) that a conductor who is lost or otherwise on the wrong track will have to phone the dispatcher and admit defeat . . .  and suffer the shame and humiliation of correcting his mistake while the other operators sit idly by or are forced to take alternative routes. I doubt this situation will happen more than once.

As for the poor design decision of having "long stretches of track parallel to the fascia and/or rear wall . . ." The entire right portion of my benchwork blatantly violates this conventional wisdom, but I suggest that what it depicts is extremely prototypical. That is what towns look like: long, straight main street intersected by cross streets at regular intervals forming (more or less) square blocks. Boring. Not to me. I particularly like the (boringly) straight double mainline. I can easily imagine the daily commuter or the six-year-old-boy standing on the platform straining to see the headlamp of the locomotive as it rounds the curve in the distance. The straightaway gives the 10- or 12-car consist of the Broadway Limited or California Zephyr room to stretch out before dipping its nose into the station siding. Once in the station, I provided some room ahead and behind so that things never look like Wilt Chamberlain trying to sit in a Volkswagen.

As for yards, the entire lower level is nothing but one large yard, about 50 feet long after unfolding the folded dogbone. Laid out and scenicked as a deep-water port, but functioning like any other yard. More or less.

Robert

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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Sunday, March 19, 2017 10:47 AM

IRONROOSTER

This reminds me of some old discussions on which scale is the best.  or Which era is the best.  or Which prototype road is the best.

There is no best and no universal rule of thumb.  Every layout we build and operate has compromises with faithfully modelling the prototype. Partly this is because we have limitations, but partly because somethings are just boring.  Do you really want to run a train at scale speed for a 20 mile stretch of track in the country with no stations or sidings (approx. 1200 ft in HO) and/or build the layout to support that? neither do I.  Do you accurately model the basement interior of every house on your layout? neither do I.

You figure out what you want to do and then how to best do it given your space, time, and money resources.  If that means running 80' passenger cars on 18" curves then that's what's right for you.  If you like to kick back and watch your 4-4-0 pull 36' boxcars around a 60" curve, then by all means do that.

BTW the best scale is not the one you're using.  You also have the wrong era.  And You need to pick a better prototype. Laugh

Paul

 

Completely agreed, but as pointed out by another poster, even 36" radius represents one of our biggest items of "selective" compression. We run 85' cars around 30" or 36" curves like it is the mainline, in real life that would be a highly restricted speed curve for an 85' car.

I understand and agree about compromises in this hobby, but without some of these discussions, some people in this hobby would never know or understand the implications of their choices until they had problems.

I want passenger cars to have close coupled working/touching diaphragms. I accept all the other compromises I need to make to get there.

In my case, I am so particular about "broad overall visual effect" that I am willing to compromise on things like scale car lengths to get a better overall look.

I run mostly passenger cars in the 70'-75' range on curves in the 36" and larger range to get better looks, better operation, and those working diaphragms.

I have a few 80' cars and they work fine, but overall the trains look better because of the slighly compressed cars on the relatively large curves.

Not to go too far off the topic, but the other benifit of the selectively compressed cars relates to your comments about scale distances and such. Rather than run passenger trains with fewer cars, I can have more cars and pull them into station platforms that need not be as long to support an eight or nine car train.

A nine car train of 85' cars is about 9' long, but nine 70' cars are only about 7' long. Nine or ten car passenger trains close coupled with diaphragms touching, that don't look like toys on curves, are much better to my eyes than 6-7 cars trains with wide gaps between cars and big overhangs on curves.....

My choices and compromises......other may be interested in how their choices will work out.

Sheldon

    

  • Member since
    January, 2009
  • From: Maryland
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Posted by ATLANTIC CENTRAL on Sunday, March 19, 2017 10:54 AM

ROBERT PETRICK

 

 
7j43k

When I first saw Robert's layout, I really liked it.  It is NOT flamboyant . . . But it REALLY feels comfortable to me.

Ed 

 

 

Hey thanks, Ed.

You know, oddly enough, comfortable is exactly what I was shooting for. I never thought about flamboyant one way or another, but I kinda like the idea of being not.

I specifically wanted a double mainline throughout for long, continuous runs that allow trains to stretch their legs. I like trains to run; to pick up stuff here and deliver it over there, and over there is usually a long way away with lots of nothing in between. I have a very low trackage-to-scenery ratio.

The only crossover of the two mains is effected by the convergence of the east- and west approaches to the Littlefield bridge shown at the bottom of the sketch. The lack of convenient crossovers means (just like in real life) that a conductor who is lost or otherwise on the wrong track will have to phone the dispatcher and admit defeat . . .  and suffer the shame and humiliation of correcting his mistake while the other operators sit idly by or are forced to take alternative routes. I doubt this situation will happen more than once.

As for the poor design decision of having "long stretches of track parallel to the fascia and/or rear wall . . ." The entire right portion of my benchwork blatantly violates this conventional wisdom, but I suggest that what it depicts is extremely prototypical. That is what towns look like: long, straight main street intersected by cross streets at regular intervals forming (more or less) square blocks. Boring. Not to me. I particularly like the (boringly) straight double mainline. I can easily imagine the daily commuter or the six-year-old-boy standing on the platform straining to see the headlamp of the locomotive as it rounds the curve in the distance. The straightaway gives the 10- or 12-car consist of the Broadway Limited or California Zephyr room to stretch out before dipping its nose into the station siding. Once in the station, I provided some room ahead and behind so that things never look like Wilt Chamberlain trying to sit in a Volkswagen.

As for yards, the entire lower level is nothing but one large yard, about 50 feet long after unfolding the folded dogbone. Laid out and scenicked as a deep-water port, but functioning like any other yard. More or less.

Robert

 

Robert, love your layout plan. I have designed layouts for others, I agree with all your reasons for breaking the "rules" you broke. And you are correct, real life is full of railroad tracks exactly at right angles to all the other man made stuff around them.

Again, great layout plan.

Sheldon

    

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  • From: Northern Virginia
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Posted by riogrande5761 on Sunday, March 19, 2017 1:21 PM

BMMECNYC

We dont need to talk like lawyers, just avoid using inaccurate broad generalizations.  

If the past 8 years on the forum are any indication, good luck with that!

Rio Grande.  The Action Road

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  • From: Bradford, Ontario
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Posted by hon30critter on Monday, June 05, 2017 11:04 PM

OP seems to be amongst the missing. Have we been trolled?

Dave

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Posted by GN goat kid on Tuesday, June 06, 2017 12:52 AM

I'm getting a lot of good info. But what is a sticky?

GNgoatkid.

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    December, 2015
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Posted by BigDaddy on Tuesday, June 06, 2017 3:19 AM

I didn't think we were allowed to use the T word.  That's why I called it a Drive By Thread on 3/16.  At least Robert made it a useful discussion.

Henry

COB Potomac & Northern

By the Chesapeake Bay

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Posted by riogrande5761 on Tuesday, June 06, 2017 8:48 AM

hon30critter

OP seems to be amongst the missing. Have we been trolled?

Dave

Dave, modus operandi around here.  We should be used to someone starting a topic and rarely if ever comign back in to respond; meanwhile everyone is busy discussing the topic for the OP like a bunch of bafoons - me included.  *sigh*

Rio Grande.  The Action Road

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Posted by carl425 on Tuesday, June 06, 2017 12:14 PM

rrinker
Despite saying you have some relatively tight radius curves, you actually have, in that plan, implemented many of the ideas being mentioned. Most of your tighter curves, the exception being the two at the top of the right hand aisle, are viewed fromt he outside, not the inside - this helps dimish the appearance issues on tighter radius curves.

You have that backwards.  It is the inside view where the tighter radius looks less toy like.  Here's the table from the much referenced MRH article that was based on the LDSIG'S original work:

2   Some equipment may track reliably, but 2x is generally considered pushing it.
2.5   Most equipment will track reliably if everything is of similar length.
3   All equipment should track reliably; coupler performance adequate if altered to allow 50% car width swing.
3.5   Equipment will look less toy-like when viewed from inside the curve.
4   Equipment will look less toy-like when viewed from outside the curve.
5   Most reliable coupling on curves with body-mounted couplers and near-scale draft gear boxes.

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.

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  • From: Richmond, VA
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Posted by carl425 on Tuesday, June 06, 2017 2:06 PM

ROBERT PETRICK
As for the poor design decision of having "long stretches of track parallel to the fascia and/or rear wall . . ." The entire right portion of my benchwork blatantly violates this conventional wisdom, but I suggest that what it depicts is extremely prototypical.

I have never seen a real railroad with a fascia. Smile

Up to the point of the fascia, I agree that many towns are laid out exactly that way.  This is somebody's idea of a good "design principal" (like not putting the sofa against the wall) misapplied to model railroading.  One poster even admitted to quoting it without understanding the principle.  It comes from the idea that a track should appear to follow geography - not to avoid running off the edge of the layout.  This is a good idea generally, but like everything else can be easily carried to far.

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.

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Posted by ROBERT PETRICK on Tuesday, June 06, 2017 3:24 PM

carl425

 

 
ROBERT PETRICK
As for the poor design decision of having "long stretches of track parallel to the fascia and/or rear wall . . ." The entire right portion of my benchwork blatantly violates this conventional wisdom, but I suggest that what it depicts is extremely prototypical.

 

I have never seen a real railroad with a fascia. Smile

Up to the point of the fascia, I agree that many towns are laid out exactly that way.  This is somebody's idea of a good "design principal" (like not putting the sofa against the wall) misapplied to model railroading.  One poster even admitted to quoting it without understanding the principle.  It comes from the idea that a track should appear to follow geography - not to avoid running off the edge of the layout.  This is a good idea generally, but like everything else can be easily carried to far.

I've been to San Francisco, and I've seen firsthand what happens when designers try to impose a rigid grid on unyielding topography. On the other hand, I was born and raised in Florida, which is flat like a pancake, and where many towns look just like the little town depicted on my layout. Imagine that. 

Robert 

LINK to SNSR Blog

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