O-72 Engines on O-60 Track?

I don't understand why folks just don't believe the manufacturer... 

Consumers tend to oversimplify the problem by thinking the minimum specifies the ability for it to track around a simple singular curve piece of that size or greater. What is forgotten are more complex track scenarios, such as S curves and clearance for switch machines in various configurations which the manufacturer tests.

To further compound the matter, there were times when the number of curve sizes was more limited (not as many graduations) and so the minimum rating may only reflect the smallest curve size fully navigable available at the time, but that generally isn't an issue with most modern issues that I see inquiries on.

Your best bet (if the minimum is close to your desired value), is to actually ask your LHS to let you take the piece and guide it over some sample track of that size for you to make the determination. An alternative would be to ask someone, say on this forum, if a very specifiv particular model will run over a particular set of track configurations like done here, but I'd hate to see this forum become 80% "does this O-96 rated engine run on O-27?"

It would help if you posted the make and model # of the particular engine.

That way, people on the Forum who have that engine may be able to chime in.

It depends on which locomotives as others have said.  Also, sometimes the minimum curve is based on the drawbar length, or the coupler throw, it's not just the locomotive making the turn.

FWIW, my Vision Line Big Boy will do an O60 curve, but the centipede tender doesn't make it, it jumps the curve.

I have a MTH Premier Santa Fe 2-10-4. It's rated for 072 minimum by MTH. It has gone around 054 tubular simple curves and switches without issue. It looks ridiculous but it runs fine. I don't run it around 054 curves often but it will work if you run it that way.

What is the model number and manufacture of the locomotive you are considering?  

gunrunnerjohn posted:

 Also, sometimes the minimum curve is based on the drawbar length, or the coupler throw, it's not just the locomotive making the turn.

GunrunnerJohn has focused on the root criterion, which I have bolded in the quote from his post, above.

Your locomotive may negotiate a sharper curve than that stated by the manufacturer, but, will the car coupled to it follow it through the curve without being forced to the outside rail of the curve?  This applies to the shortest and, more importantly, the longest, cars you may ever wish to couple to the engine.  And, of course, the overhang of the engine could sideswipe some of your scenery.

In our age, there is an easy temptation to believe that "we can have it all."

We can't.  

And lets not forget potential damage to the drawbar wires/ connections depending on make.  As the drawbar is swung from one extreme end of travel to the other. Often times forcing itself against the tender sides.

Just because you can, doesn't mean you should. I've also seen more than one video of a loco grinding its way around smaller than recommended curves and you could see where the rods had worn the paint off of the counterweight detail on the wheels from rubbing.

For the people asking what model I am looking at, is the Lionel Legacy PRR 2-10-4 Texas. And I appreciate the above replies. I didn’t think about the drawbar and I’m glad people mentioned that.  

I hope the middle drivers are blind drivers, or I suspect that will be the limiting factor.

bmoran4 posted:

I don't understand why folks just don't believe the manufacturer... 

Yes. I agree. Why would they lie and limit their market? 

The minimum "radius" (3RO diameter) is typically a conservative figure - but by a bit, if any.

My prewar Hiawatha locomotive will run on 060.  Not so with the passenger cars.

Lou N

Also regarding the 'drawbar', sometimes there are two holes in it and one must be sure to use the hole 'nearest the tender' in order to achieve the minimum curve listed by the manufacturer.

I have a friend that just bought a MTH Bipolar. The box says 072 but running freight cars behind it works fine on 060. AND yes the Milwaukee Road did run some shorter freight train behind the Bipolar at the end of those GE electrics life. Don

Four axle tender trucks don't like anything less than 0-72. John in Lansing, ILL

My experience with minimums is to err on the high side not the lower.  You may end up with a shelf queen.