O gauge and O27-what's the difference?

O Gauge is the spacing between the outside running railes, i.e. the gauge. The term 027 originally relates to a 27 inch diameter circle of track place around the Christmas Tree, i.e. the term 027, which includes non-scale size equipment forshortened to negoait such tight curves.

O-27 is often referred to as traditional and has a shorter profile than O gauge. As the other poster stated, it started out referring to the circle diameter but morphed into an entire line of track. Most newer O won't run well on O-27.

O27 track is merely a different style of O gauge track.  its origin was in the less expensive sets and is made from a thinner material, but it also has a different profile than standard O gauge track.  Marx exclusively used the O27 track profile in their sets even introduciing a wider radius (O34 equivalent) in some sets with their larger locomotives.

Uh-oh....as I had Marx trains as a kid, is it true that most modern trains will NOT run well on 0-27?  I do not like it now and want more realistic track, and I have never liked the profile of "Lionel" "O gauge".  Which is why I am still wishing for a better track system ((more realistic, with a better (low) profile, but simple to use)).  The nonelectronic stuff I run seems to run okay on O-27, and I thought I remembered that K-Line made that 0-27 profile in a variety of radii, etc.? 

This is not just a question of minimum radius, is it...that modern trains won't run well?....a Triplex is obvioulsy not going to ride around a 27" figure eight, but I am guessing that, a Challenger, or whatever runs okay on MTH Scaletrak, with its lower profile.

Your talking about the track. In postwar catalogs O meant the premium Locos, and sets where 027 meant Less expensive engines and sets usually with one motor instead of two, or less detail, plastic trucks instead of metal.

To sum up the difference:

"O" has a larger profile, meaning the track is taller.  'O' is the same height as lionel's fasttrack and there are transition pieces available to switch between these.  

O27 is shorter and made of a thinner metal.  It's not any worse, really for running your trains, but the 'standard' 27 inch diameter curves are too tight for any sort of scale engines or rolling stock.  There are wider curves available in the O27 profile such as o-42 and o-54.  The height of O27 profile is the same as most other, more scale looking track I believe, such as Atlas, gargraves and ross.  

Aside from Fasttrack, all the brands of track I'm aware of use the O27 profile.  

When it comes to the actual curve diameter, 'O' track has a 31 inch circle as the smallest diameter with 42,54, and 72 inch curves as well.  Which profile you choose is up to you and really has more to do with what track brand you plan to use.  

As for the trains themselves, the O27 were the lower cost products.  generally less quality and less detail.  Also worth noting that many of the starter set locos now seem to have trouble with the tight o27 curves as the seem to be designed for the o36 curves that are standard for fasttrack.  

Just for the sake of any one new to the hobby reading this thread, it is not a case of "most newer O won't run well on O-27." It depends whether the product is scale or traditionally proportioned.

"Many of the starter set locos now seem to have trouble with the tight o27 curves" is also an overstatement. This may be more true of the MTH starter sets, since the Railking line has gone more scale. But as far as Lionel stater locos, many STILL will run fine on the 027.  But even before the scale trend, many MTH items were listed as 031 minimum curve, when they in fact WILL run on an 027 curve. I asked MTH about this and was told, that because they did not make their own 027 track, if an item HAD NOT been tested on an 027 curve, it wouldn't be listed as being able to do so. The MTH Railking dump car is listed as 031 minimum, but IT WILL run on and clear the 027 swtich box housing as I've done it myself.

The Lionel starter set GP-7/9/20/38, U36B will all run on 027 curves, as will the 2-4-2, 4-4-2, General and Dockside steamers as well as all the Thomas locos, the industrial switcher, NW2, RS3, the older model centercab switcher, the Alco FA and many others. There are semi-scale steamers that also negotiate the 027 curve. The Harry Potter type steamer will not run on 027 curves unless it is a wider radius curve and I've read here the 0-8-0 starter steamer also has trouble on 027 27 inch curves.

Years ago I spoke with one company CEO about the changes in product labeling. He told me the train market associaties 027 as meaning non-scale or toy, and they were trying to move away from that perception. Which is sort of funny, since they also acknowledge the traditional side of the market is way bigger than the scale side, and most profits are made on the traditional end.

In current Lionel catalogs, the minimal curve listing has often been inaccurate, I suspect partly because of FasTrack being the main track line, but also I suspect out of carelessness: because some products are listed as minimal 027 curve and some are not - even though they will make the curve.

If you look at Lionel catalogs pre 2003 when FasTrack became the starter set track system, you'll see many locomotive types in starter sets with 027 track in 27 inch diameter curves. If one is using 027 track, it simply pays to ask questions before making a purchase.

I've posted this video before, but you can see a wide variety of product ALL making the 027 curve and clearing the 027 switch box housing, including some Weaver cars, which are scale proportioned. I think the Reading loco is a Williams GP38 and the WM loco is the Lionel starter set version of the GP38.

branialO27, you have way more knowledge with O-27 track than I and I see K-Line in your name lol...

Can you tell me if old K-Line tubular O-27 directly connects with Lionel O-27 no harm, no foul?

Ted

027Ted posted:

branialO27, you have way more knowledge with O-27 track than I and I see K-Line in your name lol...

Can you tell me if old K-Line tubular O-27 directly connects with Lionel O-27 no harm, no foul?

Ted

I may not be BRIANEL_K-LINEGUY, but I do have both K-Line & Lionel O-27 track. The K-Line variety is interchangeable with the Lionel, indeed, the two are all but indistinguishable from each other.

Also, a number of shorter scale-proportioned engines & cars work just fine on O-27 track. Examples include, the WBB GP-9, the K-Line MP-15, & the Lionel Standard O 2-bay ACF hoppers.

Yep Ted, no problem with either K-Line 027 track, Williams by Bachmann 027 or MARX 027 track to Lionel 027 as far as connectiions.

Cool, thanks guys! A friend has a boatload of K-Line he wanted to mail me and I wanted to be sure it will worked as I am O-27 only.

Ted

Thanks for the addeum Matt. You can add the K-Line S-2 and the RDC Budd Car - as well as the nicer RMT versions of those two products, as well as the K-Line Alco FA. And of course, many of the Williams clones of postwar Lionel engines.

This is just one of those issues where it good today to either ask questions before you buy, or do some homework. Again, going to older Lionel catalogs, the EMD FT loco, which now comes in starter sets, also originally came in starter sets with 027 track. 

There are some products where the real issue is not whether they make the tight 027 curve, but whether they will clear the switch box housing of the post 1970 turnout re-design. Here again, you could go to the older Lionel 027 switches, or Gargraves. OR if you can find them now, to the later made K-Line low profile 027 turnout.

I want to add that I have no issues with any of the Menards box or flat cars on O-27 track.

Ted

027Ted:

I second Matt's statement. My "test track" (featured on most of my YouTube channel) is comprised of Lionel and K-Line 40" straights and K-Line 072 curves of 027-height rails.

As a note of trivia, K-Line's '027' track was made of the same gauge steel as its 'O' bretheren. It felt a lot more sturdy than Lionel's

For the original poster, 027 rails were 7/16 of an inch from floor to top of rail head. 'O' was 11/16". Lionel characterized the latter as heavy-duty mainline-style track, and the former as siding and branchline track.  All this was during the time that only one curve diameter was available in each size of rail. Since that era, many more varieties of curve diameter have appeared on the marketplace, making the distinction less useful to the newcomer.

---PCJ

027Ted posted:

Cool, thanks guys! A friend has a boatload of K-Line he wanted to mail me and I wanted to be sure it will worked as I am O-27 only.

Ted

One point that's worth bringing up that I've learned, somewhat the hard way.  In the 1960-80s, my uncle and grandfather had Lionel trains.  My grandpa called his O27 Gauge, and my uncle called his O Gauge.  In concert with the descriptions above, grandpa had the lower profile O27 track with 27" curves, and my uncle had the higher profile track with 31" curves.  Also, as others pointed out above, my uncle was able to run some larger engines like the Virginian Trainmaster and the Santa Fe F3s while my grandpa ran smaller engines like a 2-6-2 steam, NW-2 switcher, a 0-4-0 switcher, and the 4-4-0 General.  Both, however, had the Union Pacific FA diesels showing that the "gauge" of the track was common between the two and that O27 engines could run on O Gauge track but not always vice-versa (due to the slightly tighter curves).

Since then, however, the market seems to have adopted the terms Scale and Traditional (some say semi-scale, but others eschew that term).  I've made this translation in my mind from old to new terminology:

1. All old O27 stuff and anything marked O27 today fits into Traditional. 

2. Most old O Gauge stuff falls into Traditional but may, as before, not run on 27" dia. curves.  These will typically need at least 31" curves.

Therefore, O Gauge and O27 are a subset of Traditional.

3. Some old O Gauge items come close or are "scale" per say but purists frequently comment that they're not prototypical in detail and therefore not "scale" by a more exacting definition.

4. Modern "scale" items go for 1:48 scale and precise detail.  As a result, many/most are pretty large and require at least 42" or 54" curves, some 72".  However, "scale" doesn't necessarily mean BIG, so a small engine in real-life will be small in O Scale and might even run on 27" curves.  That's the kicker.  There are some scale switchers that do fine on 27" curves.  Generally, O Scale products have command control, intricate details, and higher price tags.

That's how I see the market today vis-a-vis 40 years ago when I played toy trains with my uncle and grandpa.

Just to eloborate, probably because I wasn't really clear on it.  

" "Many of the starter set locos now seem to have trouble with the tight o27 curves" is also an overstatement."

Sure any design that was around since before I was born will still work fine on tight curves.  The newer 0-4-0's and 2-4-4's, though, have trouble, and these seem to be what are included in the starter sets that are being pushed at the LHS's near me, and of course the popluar polar express sets.  in fact the berk JR barely seems to manage O31 curves, where as a similarly sized hudson(4-6-4) has no trouble at all.  

O-27 is fun. Even if you use 3/16" scale instead of 1/4" scale!  LOL

I use 027 when I need a smaller track radius, like inside another track or on the upper level of my layout. I have added Gargraves switches and curves with the 027 for better operation.

Lee Fritz

O27 as a profile is available in other diameter turns than 027, there are 31, 42, 54 and now and then you can find 72 inch. There are commercially made benders that will convert straight track to any radius you desire.  

027 is bout as good as it gets, in my opinion. Bulletproof track, trains, you name it.

My observation, I have a loop of O27 in the front window display at home. 27" curves, overall 5.5 feet long. My North Pole Central 4-4-2 does not like it. Front wheels of pilot truck keep popping out. My BEEP North Pole and Snowflake and my RS-3 Happy Holidays run fine. I theorize that is why Lionel made a lot of 2 wheel pilot truck engines even though they are not strictly prototype (2-4-2 and 2-6-4 not exactly common in US). Though the diesels seem quite comfortable.

Everything else will go on 36" Fastrack for now.

Frank

Funny the 4-4-2 has trouble. My dad's old 6-8-6 turbine runs around 27" curves just as well as my Marx 0-4-0's do.