o-31 engine on 0-27 track?

It depends on the engine. I have some 0-31 diesels that easily take 0-27 curves. I have some relatively small Railking steamers (Imperial and non-Imperial 4-6-2 and 4-6-4) that will go around 0-27 curves but don't like it and serious drag results from the wheel flanges and as a result don't run them up there. What kind of engine are you trying to run? If you can run larger curves throughout, I would. I did my upper loop, originally intended to run small conventional engines in 0-27 when I could have gone bigger and wish I did. Only a select number of engines I can run up there and my layout is no longer mixed command/conventional. All command control including that "was going to be only conventional..." loop. 

I have a weaver gp-38 that will take o-27 curves with a straight piece in the middle pretty well.

 I  would mostly run railking.

The easy answer is that some will work, some won't.  Two of my O31 rated steamers won't handle the O27 curves.

I'm guessing you know that O27 track has a lower profile than O31 track. If you're running O27, you can get new 42" and 54" curves in the lower O27 profile track.  If you can find some, Marx made 34" curves for O27 track.  I have a mix of 27", 34" and 42" curves on my layout but would love to get rid of those tight 27" curves.

I have 9 Railking engines - all of which are rated for more than O27 curves according to MTH.  It's my belief that manufacturers list as the minimum whatever their track system's minimum is - in almost all cases.

I have a GP20, a 6-8-6 baby turbine, a scale SW1500, an SW9, two F3's, two RS-3's - all handle 27" curves.

The only one that won't is my Aerotrain, but I knew that going in.

I asked someone at OGR that does reviews why oh why they don't list the true minimum in their reviews. Their response was that unless the engine was tested on every brand of switch they couldn't honestly say what they min is so they go with what the manufacturer says.

I have a Lionel CABOOSE that won't handle 27" curves because the steps stop the truck from rotating far enough.

This is THE MAIN REASON that I don't buy without personally seeing/touching the item.  Most times, unless I know for sure ahead of time, I take track with me to the LHS and test the piece to make sure.

- walt

For much equipment, such as many postwar O gauge items, the limitation was never the curve diameter itself, but clearance with O27 switch machine covers.

Depending on the type of switches and machines you use, many O31 items will run on O27.

Jim

Thanks, you guys are a great help!

I have a 17" Williams FP-45 loco that has no problem running on 027 curved track.  It will NOT however, work on Lionel 027 switches.  The fuel tanks on the side of the body hit the switch cover (as noted above).  If you have the room, definately go w/ the larger curves.  I'm using Marx 034 curves (& 027) on my small 5' x 8.75' layout which workout well for me.  Good luck w/ your project.

Bob 

Don't be telling everyone about the Marx 034 track, they'll get even harder to find nice pieces

Seriously, it is a great alternative on small layouts. It will work nicely for an outer loop with 027 as an inside loop.

 

Steve

 

Originally Posted by GTBob:

I have a 17" Williams FP-45 loco that has no problem running on 027 curved track.  It will NOT however, work on Lionel 027 switches.  The fuel tanks on the side of the body hit the switch cover (as noted above).  If you have the room, definately go w/ the larger curves.  I'm using Marx 034 curves (& 027) on my small 5' x 8.75' layout which workout well for me.  Good luck w/ your project.

 

 

Bob 

Cheers,

Bob

Anyone know about the Lionel 4-4-2 E6's? Min curve on these (ie. 28704, 11315) are rated at O-31. However, like many in this useful thread some of these smaller 31 curve locos will run fine on 0-27.

If these Atlantic's take o-27 curves that's great cause I have o-27/42 switches. If someone has one, doesn't know and has some 27 track to test that would be SUPER!

I've asked this question of the MTH techs and was told....."we don't generally list items as 027 because our own track minimums are 031". Yet some of their newer switchers ARE rated at 027. This was important to me because I have some back to back 027 switches and need switcher engines that can not only make the "S", but not hit their fuel tanks. Some of my engines will easily do 027 curves but will derail on the back to backs. The SW 1500s, SW 1s and the Alco S-2s will cruise through there no problem. 

-Roger

If I may jump in with a thought - a fact, actually: I'm not trying to be funny, but the 

perfect railroad - real or model - is one with no curves and no switches. Curves and 

their evil fellow-travelers, the switches, are always opportunities for physics to spoil your

operating session.

So, where at all possible, put the very LARGEST curves and switches on you layout

at every opportunity. Don't try to make the 027 trackage "work" unless you just 

have to. You mentioned getting "larger curves":

Yes - do that. As large (switches, too) as will fit in your layout area. Worth the money

if you can swing it. Six months from now the expense will be forgotten, but the trains

will still be running better.

Really, the only way you are going to find out is to try.  I've done this trick a couple of times and it worked, and a couple and it did not.  Sometimes it matters on the length of straight, or you find out that if you use half curves or quarter curve pieces with short straights in between, that makes it work. 

But some thoughts:

• trains look strange going through these set ups - very strange: they sort of wobble
• with straights inserted the O-27 is wider diameter now: it may not fit well on the layout - might have to get wider curves anyway.
• Frankly I can't remember which manufacturer measures and rates their track based on center-rail diameter and which does it based on outside to outside rail, but ithat 1.25 inch difference is significant when there is only four inches of difference in the diameter ratings.  If the loco was made by one company and the track by another . . . could be you loco "thinks" that O-27 is actually O-29.25, and it might actually run on it . . . . 
• And sometimes the thing just runs on the tighter track despite what the manufactuer said - have you tried it to so see?

I got my K-Line Big Boy, rated at O-31, to run on O-27 track.  I went slow, and could tell it didn't care much for it, but it did it.  I just wish Atlas made O-31 track.  I understand why they don't, but I still wish they did.

With difficulty you can get Atlas flex-track to bend that tight.  I've done it.  It takes patience and attention but you can warp it around enough to do that.  If it is important to you buy a piece and experiment and see if it works for you.  

I'll have to keep this in mind.

mth premier gp38 says O-31 but will run on O-27 if that helps you any