minimum turning radius

[kherman]

I'm planning my sons x-mas present. His first HO layout. It's going to be rather cool, but before I buy a thing I want to get a plan done for a sheet of plywood.

The planning ....
It will be diesels to start. He is 4, so I don't intend on getting steamers yet. I do want to be forward thinking though. So, I should plan for a 2-8-2 to run on it eventually. I would also like to get some of the longer cars like passenger cars (which can be longer than normal cars) in the future.

I'm not worried that much about aesthetics. Only functionality. So, what is the minimum track radius I should plan on?

I'm sure it comes down to specific cars/engines but I need a general answer. I am considering doing the layout as a 5'x8' layout if I have to. Of course, I would hope to show everything off.

I have been here in the past and can not wait to talk more about modeling. For some reason, my e-mail address is no longer that of a registered user so I had to sign up again.

 

[jeffrey-wimberly]

If you're pressed for space you could go as low as 18" radius like I did, but 24" radius would be better as a minimum.

 

[Selector]

Agreed. You are constrained on a sheet of plywood, but you won't always have to have that layout. For now, every popular Mikado except brass will handle 18" radius curves with ease. If you feel you might be using snap track for the foreseeable future, Bachmann Industries does make several wider curves, and if you can avail yourself of them now (cost always goes up), they will have application on future layouts with larger steamers. As Jeffery says, 24" is far better, but is about the lowest practical radius for the HO 2-10-4 monsters such as the PRR J1 or the Texas type AT&SF or Bessemer & Lake Erie monsters.

Many of us gravitate to imagery when we find that we are getting pleasing results with our layouts. It is in the images where engines are negotiating tight turns that our models can't win back any realism. That, especially, is where sweeping curves are far better. Not only that, but you can really smoke a train through them with impunity...you don't have to creep along for fear of a front or rear truck popping out from between the rails. But, that comes later. For now, about 22" is the best you'll do on a sheet of ply and still have a couple of inches outboard of the curve to catch a tumbled engine..

-Crandell

 

[hamltnblue]

Since it's for a 4 year old (ahem) I would suggest a decent train set. You can set up the platform before Christmas without a problem. basic saw horse and plywood will do fine. Line it with basic grass mat and you're ready. The standard train set has everything you need to set up and you, oops your son will be running in no time .

 

[UP2CSX]

If you can swing a 5'x8' layout, I'd do it. That one foot of extra space will allow you to easily have 24" radius curves and squeeze in 26" curves. If you ever want to run full length passenger cars, 24" or 26" curves will give you way less grief than 22" inch curves.

 

[OldGettysk]

Here's hoping you and the son have lots of fun !!!!

 

[kherman]

Thanks for all the advice.

My son is just like me. If that is any indication, he will spend hours at a time playing with his HO scale trains!

I'm now considering doing a two piece layout. Two larger ends (4'x4' or so) with a thinner section connecting the two.

I jsut measured the area where this is going to end up and I should try to constrain it to a 4'x10' area on the floor. Doing 5'x8' might be to hard to make it worth while.

Thinking back to my childhood, I think I had 18" radius track. It caused enough headaches with derailments. Not very often, but often enough.

So, 24" is the way to go it sounds. I'm going to investigate the size and shape that I can do. I really want to shoot for the 5' width. That will allow for an ideal layout.

It's funny. AS a kid, I had 3 circles each independent, and a few switches. It's funny how I am going to try to go above and beyond that. I am going to try and make a layout that is made for 2 independant lines that can eventually be connected and added onto just in case DCC is in my sons future (3+ years from now).

THANKS!

I'l be taking pictures of the construction. I'll post them here. It won't be highly decorative, but it will be a little boys dream

 

[NYC_George]

If you plan on running passenger cars on a 5 ft wide layout I would go the max 28 inch radius curves. Eliminate all the problems that these cars seem to have on curves. If your planning on a double main make the inner main a 25 inch radius. Keep at least a 2 1/2 inch space between the tracks other wise the cars will not clear each other. In this video of my layout the 30 car coal train has no problem with the 19 inch radius horse shoe curve while the passenger train has to use the outside 26 inch radius track 1 main.

http://www.youtube.com/watch?v=tsXBHWJsbzg

In the second video "helix action" the passenger train is using one of the upper deck's 38 inch mains. The helix radius is 31 and 34.

 

[UP2CSX]

The two piece layout you're thinking about is commonly referred to as a dogbone because...well...it looks like a dogbone when viewed from above. Since I have a dogbone style layout, I obviously like the concept. The 4x4 section on the end will limit you to 22" curves because 24" radius curves will run off the edged of the layout. For what you're planning, well-laid 22" curves should work for you. The problem you'd have by going to 5' wide end section is reaching to the back. The average reach is about 33" so 4' is actually a stretch. 5' would make it impossible to reach some sections unless you have 360 degree access to the layout. Good luck and we're looking forward to seing picture of how things are coming.

 

[kherman]

I did some reading around the forums. Seems like an 18" radius will probably cause issues with some of the grades I intend on tossing in.

I have a new idea. Something like a 7'x8' layout with a hole in the middle. What is the smallest hole that two adults could sit in? I'm think along the lines of a 3'x4' cutout in the middle.

And the dogbone (and similar versions) are also something I am considering.

I am totally forgetting something though. I'm not worried about the lumber costs. What does 1 foot of HO track go for these days? Jsut a ballpark number.


NYC_George,

I loved the video. I was thinking about doing something like that. make one line on the outside that would be capable of handling passenger cars while the other lines do not take it into consideration. It's nice to see that your 19" radius is sufficient. My biggest concern will probably be graded curves (Thus my thoughts of a more elaborate layout).

 

[UP2CSX]

First, tight curves + grades = constant derailments. Second, layouts with holes in the middle = sore back, sore knees, and inadvertently ripping out half a day's worth of wiring work. I'd really urge you to stick to the dogbone idea or look into a shelf layout you can run around the walls of the room. Either of these are easier to build, easier to scenic, and easier to run.

As for track, using 3' long sections of flex track is much more cost efffective and allows you to have non-standard curves compared to sectional track. You can get 25 3' sections of code 100 for $70 or $80 for the same amount of code 83 track. Track is the one of the least expensive things you'll buy. Switches and crossovers are where the trackwork budget really gets blown.

 

[kjd]

>I am totally forgetting something though. I'm not worried about the lumber
>costs. What does 1 foot of HO track go for these days? Jsut a ballpark
>number.

I was pricing track the other day. Flextrack is almost $1.50/ft for code 83. Code 100 may be less. (Code refers to the height of the rail in thousandth of an inch. Code 100 is .100 inch tall, Code 80 is .083 inch tall. Code 83 more accurately represents current rail weight on today's main lines. Code 100 is entirely usable but is slightly heavy and as a model more durable.)

 

[kherman]

I keep thinking about doing a 4.5'x8' layout but reaching the center is going to be tough.

I also measured the room it is going in and doing a basic 4x8 sheet of plywood looks like the way to go.

We plan on moving next summer so I can do something cooler at that time. Atleast I get ot plan a layout of some sort.