1:87 Question /New to Board

Hi All,

New to the boards and want to say HI and introduce myself..... I'm a closet model railroader and have been for many years. Well, I've decided to come out of the closet and build a railroad for myself.... I'm tired of reading magazines/books and looking at the pictures going, yeah.. one day I'm going to do that.

So, that being said I'm going to build a test 2x4 diorama and see what kind of results I get before I try for a layout. Now for the question; in HO the ratio is 1 to 87. Does that mean that in the prototype one foot is equal to 87 feet in scale? and if so does that mean my test diorama will be the equvilent of a 174 foot by 348 foot patch of ground?

Thanks,

Tom

 

Yes, although most of the time we work in inches. Not always, and not when it doesn't make sense to do so, but typically, when dealing with items like piping or appliances that measure 1-40" a side, we use inches. One inch in HO is very tiny, and not practical to model unless you're a real stickler for details.

So, one real-world inch is equivalent to 87 HO world inches.

And welcome to trainboard and the gang here. I am sure you have read here for some time and feel at home.

 

Isn't it one actual inch in HO = 87.1 real world inches?

 

Welcome to TB Tom. And to the madhouse that is model railway scales

Well, HO is also scaled as 3.5mm:1 foot (ie. 1 foot of prototype becomes 3.5mm in HO).

For non-finescale Americans 3.5mm is 1/8" and a bit

 

Yes, you are correct.

 

I agree; to be scrupulous, the exact ratio is 1:87.1. I was addressing what I took to be the originator's question, and not the question, "Is the precise ratio in HO 1:87 or is it really 1:87.1?" because it is common to refer to the ratio as simply 1:87. His question was one of trying to get a handle on the correct way to orient his figuring when computing the size of his diorama.

 

Thanks Guys

Okay Thanks a lot guys. That answers the question, now I need to figure out what exactly I'm going to do.

Tom

 

HO scale

You can buy a scale ruler that is marked off in HO feet and inches, they are quite handy. For occasional measurements you can also use a calculator and divide the real measurement by 87, for instance a 40 foot boxcar would be .4597 of a foot or change it to inches first, 40 feet times 12 inches divided by 87 = 5.52 inches. For small things like handrails it works too, 2 inch divided by 87 =. 02299 inch or about 23 thousands ( might have to use .025 wire for that?) ....dave

 

Tom,

some parts you can't simple divide by 87 to get the model. For an engine e.g. the wheels are oversized. If you really divide by 87.1 you get the PROTO.87 model.
Another examples are switch stands, this is in H0 a problem. I've made my own.
Look at the NMRA site NMRA - StRPs Index and you will find a lot of information.

Wolfgang

 

If you want to add two more keystrokes you can use 87.1 instead of 87 but in practical terms it doesn't matter. 2 inches divided by 87=.02299 or 2 inches divided by 87.1= .02296 so you'd use .023 wire in either case if you could find it.
For 33 inch wheels , 33 divided by 87=.3793 while 33 divided by 87.1=.3789, they both round off to .379, and I'm glad to see that an intermountain wheel I had laying here measured .379 near the flange base so they must be pretty well built :>) .....dave

 

The problem is not the wheel size diameter, it's the flanges. Usually our wheels have RP 25 contour. With PROTO:87 wheels you have much smaller flanges. And the thickness is less. This way the guard rails at turnouts are closer to stock rails. It looks better.

Wolfgang