O scale refers to a model railroad train that is 1/48th the size of a real train—in the U.K., O scale trains are generally 1/43rd the size of the real thing while in Europe they are 1/45th as big. Like a real train, O scale model railroad trains run on two-rail tracks. The gauge of those tracks is O, which describes tracks whose rails are 1 ¼ inches apart. Even though O scale model trains frequently run on O gauge tracks, strictly speaking, the two Os have nothing to do with each other.

The letter "O" is actually a misnomer since the designation was initially conceived to identify trains that were smaller in scale than 1, which had been the standard. Since the only number smaller than 1 is 0, that’s how early O scale trains and O gauge tracks were identified. Similarly, HO was originally intended to describe a scale and gauge that is half (H) of zero, but the letter O (pronounced “owe”) crept into everyday use among model train buffs and has remained the way to refer to zero ever since.

Confused? A lot of people are. But for those who are first and foremost focused on O scale, nothing else matters. For these enthusiasts, replicating the detail of a full-scale train in an equally detailed layout is the only goal.

An O scale model train’s tracks, as it turns out, are a key part of creating a sense of realism. When an O scale train is run on three-rail O gauge tracks (the middle rail delivers the power to the locomotive) such as those made by Lionel, the train rides higher off the surface than it would in real life, thus shattering the illusion. Model railroaders who run O scale trains on three-rail tracks are known as hi-railers. It’s not quite a put down, but it isn't really a compliment, either.

Toy manufacturers in the early part of the 20th century originally embraced the O scale so they could offer customers model trains that took up less space than their standard-sized counterparts. Because they were smaller, these trains were also less expensive. At one time or another, Märklin, Lionel, MTH, Williams, Atlas, and Weaver, among others, all offered O scale trains. Fans of brass model trains are also frequently O scale acolytes because the earliest, most collectible brass trains made in postwar Japan were usually O scale.

The smaller scale took off in the 1930s, when affordability trumped most other concerns thanks to the Depression. The scale also benefited from its adoption by industry leader Lionel, which sold two O gauges for its O scale trains. Lionel’s regular O gauge track was the same width as its O-27 gauge track (1 ¼ inch), but the O-27 had a lower profile than regular O, and its thinner rails allowed all but the longest O scale model trains to make tighter turns (a circle of O-27 tracks has a diameter of 27 inches instead of 31).

Today, neither appeal to O scale purists who put accuracy and authenticity above mere convenience. There is even a vocal contingent of two-rail O scale enthusiasts who advocate for the conversion of model trains designed to run on three-rail tracks to model trains that will run on just two. This often requires changing a train’s trucks (the framework for the axles and wheels) as well as a layout’s wiring (from AC to DC), but the lower profile that results makes an O scale model train look a lot less like a toy and more like the real thing.


Best of the Web (“Hall of Fame”)

Airfix Model Railways

Airfix Model Railways

Dave McCarthy's Airfix Model Railway treasure trove is an in-depth archive of the company's plastic railway kits fr… [read review or visit site]

Gateway NMRA

Gateway NMRA

This great reference site for model railroaders, from the Gateway (St. Louis) division of the NMRA (National Model … [read review or visit site]

HOseeker.net

HOseeker.net

This site is a treasure trove of HO scale model railroad manufacturer catalogs and other reference information, inv… [read review or visit site]

Postwar Lionel Trains Library

Postwar Lionel Trains Library

Bernie Schulz’s Lionel Trains Library focuses exclusively on postwar Lionel trains and accessories. The site cont… [read review or visit site]

Eric's Trains

Eric's Trains

Eric Siegel's site displays his collection of O-gauge/O-scale trains, tracks, turntables, and other accessories. A … [read review or visit site]

Tech Model Railroad Club of MIT

Tech Model Railroad Club of MIT

MIT's model railroad club, as one might expect, has one of the best websites for learning about how people play wit… [read review or visit site]



Clubs & Associations

Discussion Forums

Other Great Reference Sites

Most watched eBay auctions    

#ltd Toy Stamp & 1950s American Flyer Train Set In Box No 5665-w Near MintPrewar Lionel O Gauge No.265e Blue Streak Steam Engine & No.265wx Whistle TenderLarge Ives Grand Central Union Station W/ Glass Dome Standard Gauge (dakotapaul)Prewar Lionel O Gauge Blue Streak Streamlined Passenger Car Set 617 & 618 & 619Lionel 1536w Texas Special Pass Set - Boxed W/ Set BoxLionel 6-25622 Milwaukee Rd Hiawatha 18" Aluminum 4 Car Passenger Set Mint 2011Mth 20-20301 Genesis Diesel Engine With Proto-sound 3.0 - Amtrak Cab No. 145Scratch Built 4-4-0 Live Steam O Gauge Locomotive & Tender For RestorationAwesome Marx Allstate 9638 E7 Aba Freight Train Set 1958Lionel Postwar No. 345 Operating Culvert Loder Boxed Good Working Condition Wonderful Lionel Vanguard Diesel Freight Set # 13058 W/ 2383 F-3s Obs DakotapaulOn3 Brass Denver & Rio Grande Western T-12 4-6-0 Pfm/fujiyama 1973 Lionel 736 Berkshire Steam Loco & 2046w Whistle Tender, Excl, Runs Fine, No Rsv.Mth Santa Fe E-8 A B A Diesel Engine Set W Proto Sound 2.0Lionel Postwar 2344 New York Central F-3 Diesels Aa Units No Res (dakotapaul)Circa 1930 Ives Blue Vagabond Set- 1125 Engine W Rubber Stamped Lettering - RareCirca 1916 Ives Wind Up Loco #25 And Ives L.v.e. No 25 Tender Mth 40-1000 Z-4000 Transformer 400 Watts 180 Watt Track Outputs O Gauge Lionel Prewar 2226-t Tinplate 12 Wheel Tender In C-7 Excellent Lionel Pre War O Grey 763e Original Hudson Engine 503338Ocs Brass Korea O Scale 2 Rail Trucks Pitman Motor Model TrainsSp&s E-1 #700 Brass Steam Engine (4-8-4) W/ Tmcc - 3rd Rail/sunset - Bnib - RareAmerican Flyer "potomac" Prewar, Tinplate, Complete Boxed "o" Gauge Set, Wow!!!!Prewar American Flyer Trains Hiawatha Loco W/whistle Tender Looks & Runs TerrifiPrewar Marx No.4000 O Gauge 391 Steam Engine & Freight Car Gimbel's Set With BoxMth 30-1433-1 Coors Silver Bullet Train Set With Proto-sound 2.0 Ex/boxMth 20-3047-1 Nyc New York Central "niagara" 4-8-4 Free Shipping!Vintage American Flyer Burlington Zephyr 9900? Train Set 1930s Streamliner Ex CrLionel Pre-war O 265e Vanderbilt Blue Engine 503070Iron Horse Precision Scale Great Northern Sw-1 Phase Painted Psc#16685 Brass Lionel 6-25623 Milwaukee Road Hiawatha 18" 2 Car Aluminum Passenger Set Mint BoxLionel Postwar 2426w Black Lionel Lines Whistle Tender, Whistles Strong! For 7733rd Rail Pennsylvania Prr Q2 4-4-6-4 Duplex Free Shipping Buy It NowOriginal Lionel 456 Coal Ramp In Ob - No ReserveLionel O-ga. Prewar Black #225e 2-6-2 Steam Locomotive & #2235w Die-cast TenderVery Scarce 100% Original O Gauge Tinplate Basssett Lowke Lms Mail Wagon SetMth Premier Gp38-2 Canadian National Diesel Engine Set Proto-sound 2.0 Pwr & NonO Scale Atlas Southern Pacific Sw8 2 RailVintage Lionel Train Set 2100 With Box Prewar American Flyer O Gauge 5 Unit Comet Streamliner SetMth 33-1005 Southern Pacific 4-8-4 Bantam Gs4 Steam Engine Daylight Special 4449Vintage Lionel 2065 Loco & 2046w Working Tender - Engine Runs Great!Lionel Very Rare 6407 Flat Car With Missile Boxed Mint NewLionel 1948 726 Berkshire Steam Engine W/ob & Extras ~superb Condition!~Circa 1914 Ives #1100 Early Electric Loco And Ives No 1 Tender O Brass Iron Horse- Common Standard Signal Bridge 2-track #15571 MibAhm Rivarossi 2-8-0 Steam Locomotive & Tender 2 Rail O Gauge - Italy - Runs! Lionel Lionmaster Big Boy 4-8-8-4 Steam Locomotive #6-38075 Lionel 18023 Western Maryland Shay Engine And Tender NrO Scale Brass W&r Ge 44 Ton Switcher Phase IcRich Yoder Models Brass C&o 50 Ton 40' Steel GondolaLionel Type Zw 275 Watt Trainmaster TransformerMth 30-20168-1 Es44ac Imperial Ge Evolution Diesel - Excellent Condition!Prewar Bing O Gauge 2 Stall Engine House Made In Bavaria GermanyHornby O Gauge Tinplate Fire Hut/hydrantCirca 1912 Ives Limited Vestibule Express Set Of Three Cars - Third SeriesNorthern Pacific A-4 Brass Steam Engine (4-8-4) W/ Tmcc - 3rd Rail/sunset - BnibLionel Postwar No. 175 Rocket Launcher In The Box Marx Prewar Union Pacific M-10000 Streamline 4 Piece SetLionel Trains Postwar O Gauge 022 Remote Control Automatic Track Switch Set O22

Recent News: O Scale Model Trains

Source: Google News

Model trains a fun hobby
The Garden City Telegram, March 22nd

Brad Nading/TelegramDavid Demers, 4, Hugoton, tries his hand at running a Thomas the Tank Engine “O”-scale train with a remote control Saturday at one of the displays during the Garden City Train Show in the Finney County Fairgrounds exhibition ...Read more

All aboard for April train show
Algona Upper Des Moines, March 12th

ALGONA — Arlen Benschoter's massive 'O' scale Lionel train display at the Kossuth County Agriculture and Motorsports Museum will be the feature of a model train show on Saturday, April 18, sponsored by the Prairie Lakes Division of the National Model ...Read more

Railroad Days to be hosted, appropriately enough, at Allen Train Depot
Star Local Media, March 11th

Local Allen resident Stan Schwartz is an active Dallas-Fort Worth O Scale Club member and is organizing the Allen exhibit. Schwartz has been collecting model trains for over 60 years. In 1952, he bought his first Model Railroader magazine and continues ...Read more

Model train show chugs into a new station March 14
Shelburne News, March 11th

The show will feature multiple operating HO, N, Z, G, and O-scale layouts in addition to over 100 tables of exhibits and vendors of model railroading supplies and railroad videos and books. There will be hands-on train activities for children also. The...Read more

Model railroad builders roll into Ogden's Union Station
Salt Lake Tribune, March 7th

HO — about 1:87 scale, or half the size of the classic O scale made famous by Lionel trains — is the most popular size of model train, Murphy said. A standard module is 4 feet long, with three lines of tracks connecting one to the next. The largest...Read more

RI train expo offers something for everyone
Quad-Cities Online, March 1st

"As soon as he said, 'Choo-choo,' we started buying Thomas," Mr. Genung said of the popular children's train toys Sunday during the Great Train Expo at the QCCA Expo Center. "We've graduated from Thomas to O scale, and now we're into HO. We're ...Read more

Model trains by the mile on view at this exhibit
NJ.com, November 18th

Members of the 80-year-old society operate a train museum and two large "railroad empires" that include model train layouts that cover almost 4,000 square feet. The larger "O" Scale layout is 40 by 70 feet and has almost 20 scale miles of train track...Read more

Massive model train club in Paterson invites Halloween visitors (PHOTOS)
The Star-Ledger, October 24th

The NJ HiRailers claim to have the largest "O-scale" layout in the country, at 185 feet by 40 feet. O-gauge refers to the scale of the layout, which is 1:48. Hunterdon County's Northlandz, which claims to be the largest model layout in the world, is HO...Read more