# Locomotive wheels vs. track radius



## bile (Dec 14, 2009)

Hello, i just started a ho scale layout. What i was wondering is, i use 18" radius pieces for my curves. what is the biggest size loco. wheel scheme that can safely handle this radius? My 0-6-0 can make these turns just fine, but the 10 cars that i hooked up, well lets just say my loco can only pull 5 before getting hung up. i read that loco's like 4-10-4 and such would be too big. Lookin for a good steam loco.


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## tjcruiser (Jan 10, 2010)

You're thinking is on the right track, though any hard answer is dependent upon each specific loco (and car, like a long passenger car). Some manufacturers will post in their product descriptions the minimum recommended track radius.

Cheers,

TJ


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## tkruger (Jan 18, 2009)

The largest steamer I have been able to run on an 18r turn is an 0-8-0. That being said I believe both Mantua and Riverossi at one time made articulated steamers that could take 18r turns. Another issue to keep in mind is that the tighter the radius of the turn is the greater the pulling ability of the locomotive will be decreased regardless of its size. This is because the inside wheels must slip to go around a turn and are not producing any tractive effort. One method to increase the pulling power of your current locomotive is to see if there is a place in the boiler to add weight over the drive wheels.


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## bile (Dec 14, 2009)

Well, I looked at my loco. for a long time and said to myself,.. I'm not going to do this! I am not confident enough to not screw up the loco. So I'm not going to consider taking it apart. I will do some homework on 0-8-0 steamers that I like. I know this is going to be an unheard of comment from a railroad junky but,.. I only want to buy 1 really nice loco. hopefully that meets all my specs. So taking my time and spending a few bucks are ok by me. I know as soon as I purchase 1 though, I will move and end up having enough space for 22's. Which opens the options greatly.


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## Big Ed (Jun 16, 2009)

bile said:


> Well, I looked at my loco. for a long time and said to myself,.. I'm not going to do this! I am not confident enough to not screw up the loco. So I'm not going to consider taking it apart. I will do some homework on 0-8-0 steamers that I like. I know this is going to be an unheard of comment from a railroad junky but,.. I only want to buy 1 really nice loco. hopefully that meets all my specs. So taking my time and spending a few bucks are ok by me. I know as soon as I purchase 1 though, I will move and end up having enough space for 22's. Which opens the options greatly.



Eventually you are going to have to perform maintenance on it.
No lube you will kill it.


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## tooter (Feb 26, 2010)

bile said:


> I know this is going to be an unheard of comment from a railroad junky but,.. I only want to buy 1 really nice loco.


Yeah, I know, bile... I said that 5 locos ago. 

They're like potato chips... you won't be able to eat just one. 
But get a really nice one that you will appreciate just the same, and don't forget to take look at the shays, climaxes, and Heislers, just in case you might want to run an old fashioned logging train.

Greg


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## gunrunnerjohn (Nov 10, 2010)

I have about 15 engines of various types in the closet, they get rotated. I can't imagine just having one. Of course, then there's the stuff like handcars, crew bus, track cleaner, ballast tamper, etc. I don't consider them "engines", but they are self-propelled.


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## bile (Dec 14, 2009)

Big Ed,.. i've thought of that, and know I will have to do that, but I cant even begin to figure out how to take my loco. apart. It is just a little 40$ steamer, so i'm not to worried. But I cant deny a 3-5 hundred $ loco. it's drink of lube. I gather I can buy a book on how to maintain a big boy. Choo Choo,. that's funny. I've never heard of those companies you've stated. Dumb question,... your pic,.. is that a logging train?


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## NIMT (Jan 6, 2011)

Bile,
Shays, Climaxes, and Heislers are not companies they are types of steam loco's. :laugh:  All the logging companies and most of the mining companies used them.:thumbsup:


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## tjcruiser (Jan 10, 2010)

Well, actually ...

"All Climax locomotives were built by the Climax Manufacturing Company (later renamed to the Climax Locomotive Works), of Corry, Pennsylvania."

Ditto for Heisler. Shays were named after their inventor, Ephraim Shay.

So the naming of locomotive types go hand in hand with the companies and people behind them.

Cheers,

TJ


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## NIMT (Jan 6, 2011)

My Bad.
I was thinking like, Weyerhaeuser, Bosie cascade, Stimson Lumber.


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## bile (Dec 14, 2009)

I'm set now, I got something new.Niiiiiice.


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## tooter (Feb 26, 2010)

Hey bile, can you post a pic of your engine? 
I wanna see I wanna see I wanna see! 

Greg


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## bile (Dec 14, 2009)

Well, if ya can walk me through how to do it on here I'd be more than glad to. It's a Mikado.


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## NIMT (Jan 6, 2011)

Bile,
This link will help you with picture uploads.
PICTURES POST LINK


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## bile (Dec 14, 2009)

*the new loco.*

thanks for the help for the pics. will try to get 1 up by the end of the weekend.


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## zzlentz (Feb 21, 2011)

Being new to the hobby.....I am building my RR on a 4x8 sheet.Will this be big enough to use 22"radius curves?Track will use the outside edge of layout,using the whole width and length of sheet.I can then run longer Trains,can I not?


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## tjcruiser (Jan 10, 2010)

ZZ,

I assume you're talking HO here?

22" radius will work on a 4x8. The 22" is referenced to the center of the rails, so, a half circle will be about 46" diameter to the outer edge of the rr ties. One silly tip ... consider using a sheet of MDF instead of plywood ... for some reason, a standard sheet of MDF is 49" x 97", buying an extra precious inch in each direction!

As far as whether 22" is large enough for your trains, I'd say typically yes, but it really depends upon your specific choice of loco and cars. Some very large locos and cars could warrant larger radius curves.

TJ


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## Jammer Six (Feb 10, 2011)

Speaking as a former general contractor, plywood is made for decking, forms and sheathing. It must, therefore, fit 16" and 24" layout without cutting.

MDF, on the other hand, is made to be cut up in the furniture industry. Its primary value is that it's cheap and extremely stable. But a 4x8 sheet would be a bodaciously huge sofa, so MDF almost always gets cut up.

Given that it's made to be cut up, the extra inch in either direction is for saw kerfs.

You cut a sheet of plywood in half, and you don't have two pieces that are 24" wide-- you lose the saw kerf. On the other hand, you can run five or six saw kerfs through a sheet of MDF and still have pieces that are standard widths.

And now you know.

Let me know if you need any other useless trivia. I'll trade it for N scale engines.


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## zzlentz (Feb 21, 2011)

Thanks Jammer and TJ, I have been studying the situation and have decided to go at LEAST 8x12. I want more than one train,and large enough to pull multiple stock with ease,
NOT just the Engine,2 cars and caboose.How big a Radius would HO need to run smoothly?


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## tjcruiser (Jan 10, 2010)

Jammer -- interesting ... I like the saw kerf explanation.

ZZ -- it all depends on your specific choice of locos and cars. If you have some specific in mind, often the manufacturer will list minimum suggested track radius.

TJ


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## bile (Dec 14, 2009)

*locomotive wheels vs. track radius*

I'm VERY new to the hobby, but here is what I see.I have 34'-36'-40' and 50' cars running on 18" radius.My 50'ers are a tad over 7" long. They look kind of odd going around the turns. The two 50'ers I have, I like, so I will keep them. But all the future cars I purchase wont go over 40', until I change to a bigger radius.---HO scale.


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## gc53dfgc (Apr 13, 2010)

cars are rarely the problem for makeing a radius of curve. They just stick out emensly on small radius and look odd. The problem is when you get to trhee + axle bogies that the cars ride on. These usually cannot make turn radius's smaller than 22 and some will manage 18 but never 15. The more wheight and how well the bogies turn will determine if can even do a 22 radius.


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## lilpuu (Sep 25, 2011)

Okay after reading about the 18: radius, on my 4x6 table I have 18 r around the turns. Can I change the curves to 22"? and then move to a bigger locomotive?????


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## lilpuu (Sep 25, 2011)

How about a 2-10-2?


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## Massey (Apr 16, 2011)

The largest safe diameter curve you can use on a 4' sheet of ply is 22". that leaves you with a total diameter of 44" and a margin on each side of 2". I have built layouts on 4' stock before and used 22" radii and everything worked great.

As for the engines that 2-10-2 you are looking at may not like anything less than 24". The 10 drivers provide a large wheelbase that is not going to like sharp curves unless the middle drivers are "blind" which means no flange.

If you like the look of the larger steam engines take a look at something articulated. The Athearn Big Boy can take 22" just fine. I have a 2-8-8-2 from Proto 2000 Heritage that can handle 18" just fine even though it looks kinds funny. My spectrum 2-8-0 Consolodations will run 18" and play nice, but my 4-8-2 will derail every time. It is all up to how the engine was built and what the manufacturer did to help it through the tight corners.

Massey


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## bile (Dec 14, 2009)

I'm still super new to this hobby so the only chiming in I can do is,.. I have a 2-8-2 Light Mikado #9631 Steam locomotive, and I run it on 18" radius. I personally think it looks ok, but I'm sure some experts on here would see it, and pick out the small oddities with it. I go with what I like IF it works. Cant wait to get some pics on here to show everyone what I've learned so far from great people here.


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## raleets (Jan 2, 2011)

bile,
Glad you've adapted the "it's mine and I like it" attitude. 
As a raw rookie in January of this year, I went about designing my layout to please whatever appealed to my eye. Guess what? It worked out pretty danged good and I have a ton of fun playing with it.
Part of the layout includes a figure-8 with 18" curves on which I run a Bachmann 2-6-2 steamer. It runs like a charm at full speed.
Keep on keepin' on and you'll have tons of fun!
Bob


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