why?

[florynow]

Every time I log on I see at least one variant of the same question:  "how small a radius of a curve can (blah-blah-blah-blah-blah)?".

Why?  What is the root of the drive to go so small when bigger is better?  I don't believe it is limited space.  My layout is U-shaped and 15" maximum wide including the 90 degree junctures and yet my smallest curve is 22" radius, the other is 28" R.  I think it's the idea of squeezing more railroad out of limited space but my thought is that "less railroad more realistic" is much better than "more railroad less realistic."

PF

[Ken G Price]

This is almost always from a newbie wanting to run large six axle or large steam.
Like many other things in model railroading there is a learning curve on track radius.

I started this newest layout with 4 axle GP38-2's and 40 foot cars so the 9.5" was ok.
Then like many I decided that I wanted to move from the mid 70's to the mid 90's.
Well then, this called for adding some 6 axle engines and 50' plus rolling stock.
I realized very soon the error of my ways.
So now after much reworking of the track the smallest curves are 11".
Worth every bit of effort to correct this lapse of judgment on my part.

[Jim Banner]

Point to point layouts are not for everybody.  Many of us enjoy showing our handiwork to friends, neighbours and relatives as well as running our trains back and forth.  But we usually do not enjoy both at the same time.  Visitors like to see trains running and they enjoy talking about them.  They are not so interested in looking silently at your back as you do some fancy switching maneuvers.  Thus many of us include loops, hidden or otherwise, in our track plans so that both we and our visitors can enjoy the best of both worlds.

Unless you are modelling in Z-scale, I doubt you can achieve continuous running on a 15" maximum width, U-shaped layout.  In H0 scale, it takes at least 3-1/2 feet of table width for a return loop or semicircle of track.  This is already a foot too wide to comfortably work on if the table is against a wall.  Increasing track radius to 22, 24 or 30 inch radius increases table width to 4, 4-1/2 or 5-1/2 feet, all of which require access from both sides or well placed access hatches, both of which may be beyond the space, skills or interests of the modeller.

Not everybody who starts a model railroad envisions a basement or garage full of trains.  More likely they are thinking of a smaller layout that fits comfortably in a corner of the family room or on the bottom level of Juniors bunk bed.  Something around 3-1/2 feet by 5 or 6 feet.  Often it is a major step to expand their idea to 4 by 8 feet even though that greatly increases their layout's potential.  If they do convince their spouses, parents or themselves that the increased size is justified, they are not about to reduce that potential by using larger radius curves - besides they already have the 18" radius curves that came with their set.  It is only later when they want to add more locomotives and rolling stock that they discover that not all of them will run on their choice of curves.  So there are many questions of the form "how small a curve can locomotive X and rolling stock Y run on?"  Even though we may see these questions as repetitious, they are still valid questions from people who need to know, and each and every one of them deserves an answer.

So now you know why.

Jim

[Desertdweller]

Well stated, Jim.

A U-shaped layout with the dimensions given in the original post could only be built as a point-to-point.  Nothing wrong with that, as long as the builder accepts the limitations inherent in that design.

Nothing was said about what scale was used.  I had an N-scale railroad that was 7 1/2' x 22 1/2".  Curve radius was 9 3/4".  Its small size enabled its longevity: 28 years.

Les

[RAM]

Well the older I get, and I am getting old, I think smaller is better.  Not that they layout needs to be small but less trains.  The more locomotives you have the more time that must be spend on maintaining.  You can spend a lot of time switching cars out.

[Bucksco]

Why?
The answer is simple....
Why not!

[richg]

When I get bored, I sometimes ask myself the same question. The answer comes back to me. I am bored so I forget about it. It is just, blah, blah, blah stuff.
Some people have trouble researching what they want and what they can realistically do.
I remember my Lionel train days.

Rich

[NarrowMinded]

Why? Why do so many people assume everyone is a rivet counter and wants a prototypical layout?
There is no one way to build a layout, it relaxes me to just have a train running around and around, I have limited space and like on30 so I have to build the tightest curves i can get away with
I have zero interest in switching layouts, I build small layouts that are just continuous circles, theres a trolley running a endless 22" diameter (not radius) circle under my coffee table as I write this.

Also if I see another loco that I like I will ask how tight a radius it will run on to determine if it will run on my layout, this is much better then ordering one online placing it on the track and then watching it derail.

Why? Because it's what I want.

Nm-Jeff

[Johnson Bar Jeff]

Why? Why do so many people assume everyone is a rivet counter and wants a prototypical layout?
There is no one way to build a layout, it relaxes me to just have a train running around and around, I have limited space and like on30 so I have to build the tightest curves i can get away with
I have zero interest in switching layouts, I build small layouts that are just continuous circles, theres a trolley running a endless 22" diameter (not radius) circle under my coffee table as I write this.

Also if I see another loco that I like I will ask how tight a radius it will run on to determine if it will run on my layout, this is much better then ordering one online placing it on the track and then watching it derail.

Why? Because it's what I want.

Nm-Jeff

Me, too.
Well said. 

[Ray Dunakin]

Point to point layouts are fine but most of the time I like to just watch trains run.

[ChrisS]

i have a 9' x 14' on30 layout... some curves are broad for the mainline, some are 15", going to the sawmill and such.. just like the prototype, different locos can only operate on certain areas, keeps the interest up... and it is a folded dogbone, cause sometimes i just like to sit on the stool and watch them go around..

cause i can, its my road, thats why..     

[Johnson Bar Jeff]

cause i can, its my road, thats why..     

Rule #1: It's my railroad.

Rule #2: Refer to Rule #1.

[rogertra]

cause i can, its my road, thats why..     

Rule #1: It's my railroad.

Rule #2: Refer to Rule #1.

An oft used rule to excuse poor planning, unrealistic scenes and a whole mess of unprototypical modelling.

[ChrisS]

im sorry my railroad doesnt live up to your standards... count rivets much do you?

[Ken G Price]

Chris,  Much agree do I.
I agree that a folded dog bone is the way to go if one has the room.
It gives the appearance and interoperability of of a point to point, yet trains can be run roundy round if  so desired.