# How to determine gauge from model number



## theimager (Dec 5, 2013)

I have a 1955 Lionel O gauge set I got as a child. I want to expand and get another locomotive. Referring only to Lionel post-war items I am confused by the model numbers. Does anyone know if it is correct to assume that the 4 digit models, e.g. 2025 would be O27 and the 3 digit models are O gauge ? Thanks all.


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## sjm9911 (Dec 20, 2012)

That's correct for the post war stuff. I don't know obout the newer trains. I believe that Guage is the distance between the rails. The difference between o and 027 is the degree of the curve. Also 027 track isn't as high as o track. O27 stuff will run on O Guage track. Sometimes o and o27 trains are identical except for there number designation.


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## servoguy (Jul 10, 2010)

I have a 2025 steamer that is O gauge. It says O Gauge on the name plate on the bottom of the loco. I also have a 2025 steamer that is O-27 gauge. 

For diesels, the number designations of 4 digit vs. 3 digit seem to be inconsistent. I have an Alco that is a 2023 but is O-27. I have F-3 diesels 2333, 2343, and 2353. These are all O gauge.


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## Big Ed (Jun 16, 2009)

theimager said:


> I have a 1955 Lionel O gauge set I got as a child. I want to expand and get another locomotive. Referring only to Lionel post-war items I am confused by the model numbers. Does anyone know if it is correct to assume that the 4 digit models, e.g. 2025 would be O27 and the 3 digit models are O gauge ? Thanks all.



Welcome to the site.

Do you know about this site?
It has all the Postwar Lionel trains ID'ed in it take a look,

http://www.tandem-associates.com/lionel/lionellocomotives.htm


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## sjm9911 (Dec 20, 2012)

Good point, servoguy, I forgot about the diesels.


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## servoguy (Jul 10, 2010)

The tandem-associates web site has a mistake. It claims the 2025 locos were all O-27. Not so, as I have an early 2025 2-6-2 that is O gauge according to the name plate on the bottom and according to the O-31 track that it came with. I got it from the original owner back about 1955. It does not have magnetraction but does have the nickel rims on the wheels. The later 2025 2-6-4 I have is O-27 gauge as the track it came with is O-27. I bought it from the original owner about 1964.


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## Big Ed (Jun 16, 2009)

servoguy said:


> The tandem-associates web site has a mistake. It claims the 2025 locos were all O-27. Not so, as I have an early 2025 2-6-2 that is O gauge according to the name plate on the bottom and according to the O-31 track that it came with. I got it from the original owner back about 1955. It does not have magnetraction but does have the nickel rims on the wheels. The later 2025 2-6-4 I have is O-27 gauge as the track it came with is O-27. I bought it from the original owner about 1964.


You ought to send them an e mail. 

I didn't know if he ever saw the site. :dunno:


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## sjm9911 (Dec 20, 2012)

Could the motor or name plate have been Replaced at some point? Or they could have easily ran out of a part and used whatever was avaliable. ?


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## gunrunnerjohn (Nov 10, 2010)

I suspect your "O" gauge 2025 will run on O27 track.


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## rkenney (Aug 10, 2013)

My understanding was that the 675 was the 'O' version of the 2025. The 675 and the 2025 are both identical right down to individual part nos. 

I have 2 - 2025 engines, they are both marked 'O' gauge on the nameplate but run just fine on 'O27.'

Can't swear as to the parts all being original, in fact my second 2025 needed heavy restoration , including motor, steam chest, E unit , and of course the smoke element (always update to liquid.)

My current project is a 2026 (2nd version) which ironically shares the same style motor (installed backwards) and the front pilot of the 675. It is marked 'O27' on the nameplate.

I would conclude that some 2025's were built with nameplates intended for the 675. Regardless they are 'O27' locomotives purely on the basis of their wheelbase.


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## servoguy (Jul 10, 2010)

The O gauge 2025 that I have was probably purchased in 1947 or 1948.


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## servoguy (Jul 10, 2010)

My 736 runs on O-27 track just fine. It won't go through 1122 or later switches, though. I haven't tried it with the Marx metal switches, but I suspect it will go through them just fine.


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## FM Trainmaster (Nov 13, 2013)

theimager said:


> Does anyone know if it is correct to assume that the 4 digit models, e.g. 2025 would be O27 and the 3 digit models are O gauge ? Thanks all.


The 2321 Lackawanna FM Trainmaster was always sold as O-gauge, and will NOT navigate a 27" turn, so it seems this rule is not consistent.


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## theimager (Dec 5, 2013)

*Car size O vs O27*

Thank you all very much for this information and for the links. I guess that it for the steamers the 3 digits are generally O and the 4 O27 but can be inconsistent. I was looking at a 2025 and rejected it because I thought it was O27. I may have been incorrect. 

I understand the gauge and curve dimensions of the two tracks. My track is all O gauge. I was under the impression that O27 cars and locomotives were slightly smaller and in the latter case less powerful than their O gauge counterparts. In general is this true ?

Thanks again.


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## rkenney (Aug 10, 2013)

theimager said:


> I was under the impression that O27 cars and locomotives were slightly smaller and in the latter case less powerful than their O gauge counterparts. In general is this true ?


Not at all. O27 came about simply because the larger radius curves take up too much space. From a marketing standpoint that was a severe limitation. Think of all the apartment dwellers who couldn't benefit from this obsession because of their living space or lack there-of.

As far as size and power go, none of the post-war enigines or cars are true 1:48 scale and there aren't but two or three motors to my knowledge to power these locomotives, the 675 and 2025 for example are 100% identical (save for model year irregularities/changes). The really big distinction was Magna traction, and how much of a benefit it was I couldn't say (don't own one - yet). I may not even need one (not that that stops us) for I don't run very long or heavy consists.


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## sjm9911 (Dec 20, 2012)

check out the sticky in this section, confused about size etc.. you can see all the variance's in some of the o gauge stuff!


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## FM Trainmaster (Nov 13, 2013)

Magnetraction is very cool, rkenney. I remember pulling trains 20+ cars long with my 2321, as a kid. I'd have problems with the long train toppling itself in curves, before I'd run out of traction or power on that engine.


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## theimager (Dec 5, 2013)

Thank you, but I cannot find sticky ? Do you have link ? Thanks.


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## theimager (Dec 5, 2013)

*Surprised with O27 Size*



rkenney said:


> Not at all. O27 came about simply because the larger radius curves take up too much space. From a marketing standpoint that was a severe limitation. Think of all the apartment dwellers who couldn't benefit from this obsession because of their living space or lack there-of.
> 
> As far as size and power go, none of the post-war enigines or cars are true 1:48 scale and there aren't but two or three motors to my knowledge to power these locomotives, the 675 and 2025 for example are 100% identical (save for model year irregularities/changes). The really big distinction was Magna traction, and how much of a benefit it was I couldn't say (don't own one - yet). I may not even need one (not that that stops us) for I don't run very long or heavy consists.


Thanks for this info. I guess I was all wrong. I thought I remembered my Dad telling me about the smaller size about 50 years ago and so I just assumed that was the case.


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## FM Trainmaster (Nov 13, 2013)

Cost was also a (possibly the primary) distinction between O and O-27. It's been written many times, that the O-27 kits were marketed as a lower cost entry point to O gauge.


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## Big Ed (Jun 16, 2009)

theimager said:


> Thank you, but I cannot find sticky ? Do you have link ? Thanks.


Did you read the link I threw in?
The 3 or 4 number is explained there.
And it was referring to the STEAM locomotives for size. NOT DIESELS.


O27 Gauge - you’ll note that Lionel used four-digit numbers for these locomotives.
0-6-0 Lionel switcher 4-4-0 Lionel American 2-4-2 Lionel Columbia 2-6-4 Lionel Adriatic Lionel 4-6-4 Hudson Lionel 4-6-4 Hudson
spacer

>>>>Note: The exception to this is the 200 Series of Locomotives that were based on the earlier 2-4-2 No. 1130 Scout design.
<<<< Note...the #242 loco is an O. It is on the list.

O Gauge - for their O Gauge locomotives Lionel used a three-digit designation.
4-6-4 Lionel Hudson 6-8-6 Lionel Pennsylvania S-2 Steam Turbine 2-6-2 Lionel Pennsylvania K-4 2-8-4 Lionel Berkshire 4-8-4 Lionel Norfolk & Western Class J 4-6-4 Lionel New York Central Hudson

I don't know about the case of servoguys loco? As the 675 was the 'O' version of the 2025, I think someone put the engine from the 675 into the 2025.

But the 3 or 4 number was used for STEAM, not for DIESELS.

Now if you go back to this link, http://www.tandem-associates.com/lionel/lionellocomotives.htm
The page it opens up to explains all of this. 

All the 3 numbered locomotives (STEAM) are the exception they are the 200 series. Which are listed O/27.
EVERYONE FORGET ABOUT THE DIESELS.





To find all the O stuff here,
Go click forum home,
Then click O scale, (all the O threads are here)
The first thing you will see is the Sticky thread (the sticky's are always here ) 
There are 3 sticky's that stay at the top.

Here is the link for size reference,
http://www.modeltrainforum.com/showthread.php?t=5126

Looking for help info on O?

That is the third sticky down,
http://www.modeltrainforum.com/showthread.php?t=5946

O gauge parts is the second sticky,
http://www.modeltrainforum.com/showthread.php?t=8090

Though you have to search through the whole thing to find stuff in the info sticky.
It need to be alphabetically set up to look through it or something. It need to be organized somehow.

There is a ton of help there it is just kind of hard to find specific things.

One way to find specific info is to do a search, keep it simple, a lot of times the word has been tagged in a thread and will show up in the results.

But as always don't be afraid to ask if you can't find something or need to know.
Someone will try to help. :smokin:


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## Krazikev (Nov 28, 2013)

I am still new to this but I can tell you that I just mixed o gauge track with o27 track and it runs together fine I had to squeeze the track together with needle nose pliers cause I believe the o27 pins are smaller that the o gauge has anyone else done this or are there other ways????


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## Big Ed (Jun 16, 2009)

Krazikev said:


> I am still new to this but I can tell you that I just mixed o gauge track with o27 track and it runs together fine I had to squeeze the track together with needle nose pliers cause I believe the o27 pins are smaller that the o gauge has anyone else done this or are there other ways????


They sell a transition pin O to O/27.
The O tracks pins are a bit larger. The O track is a bit taller.

You can make your own with nails, we have a thread hold on.


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## Big Ed (Jun 16, 2009)

Here you go,

Making your own pins.

http://www.modeltrainforum.com/showthread.php?t=2471

Buy transition pins?

http://www.modeltrainstuff.com/Gargraves-O-802-O-27-Gauge-Track-Mating-Pin-p/gar-802.htm

It is best to join the O to O/27 in as few spots as possible.


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## sjm9911 (Dec 20, 2012)

I just squeeze the o pinin the o27 track, never had a pproblem. Also luaune makes up the difference under the o27 pretty well. If your going for even track that is.


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## Big Ed (Jun 16, 2009)

sjm9911 said:


> I just squeeze the o pinin the o27 track, never had a pproblem. Also luaune makes up the difference under the o27 pretty well. If your going for even track that is.


What is a luaune?


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## sjm9911 (Dec 20, 2012)

Luaune, I thin peice of water resistant plywood, it's the perfect height to make up the difference under the 027 track to raise up to the o. I think I spelled it right?


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## FM Trainmaster (Nov 13, 2013)

Used under tile floors, etc. mahogany plywood, typically 5mm to 1/4" thickness.


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## theimager (Dec 5, 2013)

FM Trainmaster said:


> Cost was also a (possibly the primary) distinction between O and O-27. It's been written many times, that the O-27 kits were marketed as a lower cost entry point to O gauge.
> 
> Ah... well in some ways that confirms what my Dad said. He indicated that we had the better trains at O gauge and I guess I just assume that indicated they were bigger. Thanks.


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## theimager (Dec 5, 2013)

big_ed thanks very much for all this information. Much appreciated.


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## rkenney (Aug 10, 2013)

sjm9911 said:


> Luaune, I thin peice of water resistant plywood, it's the perfect height to make up the difference under the 027 track to raise up to the o. I think I spelled it right?


Actually the luan plywood is not water resistent although I guess it could be (marine grade - if they used water proof glues). Often called Phillipine mahoghany it is most often used inside as floor underlayment for vinyl tile, also used for those craft DIY dollhouses.

Lighter than plywood, about 1/4" thick.


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