Curves and rolling stock?

Well you can't really expect a scale 89ft flatcar to negotiate o54, o42, or o31 can you? If you model 1940/50s most rolling stock was only 40 or 50 feet long and any of those will work on o31.

A tight curve on a modern prototype railroad scales out to O-240 (yeah, that's 24 feet on diameter).if you have space limitations you can switch to a different scale, switch to selectively compressed models, switch to modeling pre WW-2 era trains, switch to modeling specialty settings were short equipment is prototypical.

it's actually a little better than that.  O240 (which is 20' diameter) equates to a 12° curve.  the tightest siding curves were on the order of 20° or in 1:48 scale, O146 (even a Big Boy could negotiate a 20° curve), but the sharpest Class I Railroad mainline curve used to and still may be 6° (which would be O480 or 20' radius).

Well, I could barely do those class 1 curves in N scale in my trainroom.  The largest diameter I can fit is about 12 feet.  I have noticed a lot of O-54 stuff lately but I have two loops that run that, so I'm okay with it: longer/bigger cars are, I think, part of the push for scale stuff and modern stuff.  I'm part of that trend so I can't complain.

though not as severe as 3-rail O, most model railroads push curve limits.  a 40" radius in HO is usually considered generous, but is still a 20° curve.  even with outdoor live steam railroads, many 7.5" gauge (1.5" scale) tracks use a 40' minimum radius which as large as it looks is also just about 18°.

Along with larger rolling stock, you may also need a larger engine to go thru the curves without derailing. Atlas 21 inch Amtrak passenger cars will need an SD-40 or U33C diesel engine because these have three axles per truck, even on 042 Gargraves curves.

You don't want to forget about knuckle coupler end-play with Lionel style couplers.

 

Lee Fritz

Just ran into this problem, as a matter of fact.  Recently I started saving my pennies for the lovely Polar Railroad Conventional 4-6-2 K-4.  I'm generally opposed to paying more than a few hundred dollars for a locomotive, but I find that thing intoxicating.  As I was ogling it on Lionel.com, I was dismayed to see a minimum O54 curve; everything on my layout is O36.  Very bummed!

 

As products become more and more prototypical, I'd imagine backwards compatability to O27, O31, and O36 will decrease.

10° minimum curves are a typical standard for some mainline railroads through mountainous terrain, such as the Cascade Route in Oregon. With numerous 10° curves and lengthy 1.8% grades, the speed limit is generally 20-25MPH. Cantara Loop in Northern California is a 14° curve, which is sharper than usual for a mainline railroad. A well-engineered logging or branchline railroad might have 16° minimum curves.

 

Our typical curves for 3-rail O-gauge are proportionately sharper than what is generally used for scale equipment in HO.

It is all in what you buy.

Starter sets will always be tighter curves and smaller equipment.

Moderate size cars and engines are available for mid to small radius curves from many makers.

Scale modern equipment models are going to need those really big curves, and even bigger ones to look right.

I'm lucky in my new space where I'm building a layout.   I have 1 curve that is O-81 and the rest is O-100 and larger.   I'm using all Atlas flex track with graduated curves.

 

Oddly, I've become picky about the "gap" between the steam engine and tender and I've been shorting draw-bars by a lot.   I have a feeling many of my steamers won't make O-72 any more.

Gentlemen,

   Russell is right on the money, if you want to run 027 type trains you are going to need to look at the starter sets, you can not expect to run scale 0 Guage trains on this kind of starter track.  Remember also if you run the O Guage larger rolling stock

you must have the large radious switches to accommodate the rolling stock, 022 type Lionel switches will not get the job done for these type of trains.  Even the original O guage Tin Plate really needs the 072 type switches with 048 curves to run without problems. 

PCRR/Dave

To answer your question, yes.  We customers are the problem as we have asked for more and more scale stuff.  As stated above though you can solve the problem with selective purchaes that fit your layout.

.....

Dennis