1 gauge, gauge 1 or gauge one is a model railway and toy train standard that was popular in the early 20th century, particularly with European manufacturers. Its track measures 1.75 in (44.45 mm), making it larger than 0 gauge but slightly smaller than wide gauge, which came to be the dominant U.S. standard during the 1920s.

Thus, a one-gauge (also called “1 bore”) punt gun would have a barrel diameter of 1.69 inches, a 2-gauge of 1.33 inches, and the more common, 8-gauge, with a barrel diameter of .84 inches.

Gauge was determined from the weight of a solid sphere of lead that will fit the bore of the firearm and is expressed as the multiplicative inverse of the sphere's weight as a fraction of a pound, e.g., a one-twelfth pound lead ball fits a 12-gauge bore.

Explore top Gauge 1 model trains: live steam, vintage, electric from Aster to MTH. Enhance your collection. Shop today!

Shop unique Gauge 1 Model Railroads & Trains, from vintage figures to rare locomotives and track accessories. Perfect for collectors and hobbyists alike.

Shop our selection of Gauge 1 Model Railroad Train Tracks. Find everything from straight tracks to curved switches and expand your setup with quality pieces!

Choose a manufacturer below and look for 1 Gauge to see trains, buildings, accessories and more. AVT specializes in rewritable sound modules so you can update or change sounds anytime you wish. You can easily download any sound you want and place the speakers anywhere on your layout or diorama.

KM1 offers exquisitely detailed 1-gauge locomotives and rolling stock in limited runs. Known by collectors for their innovation, KM1 was the first 1-gauge manufacturer to offer realistic warm light LED lighting, wheel-synchronous smoke, independent cylinder steam, and their exclusive 'Dynamic Smoke' system.

Marklin - Gauge I Technology version of the steam locomotive S 2/6 of the K.Bay.Sts.B.

Gauge One requires a track gauge of 1¾ inches (44.45mm) which is generally referred to as 45mm. In practice this means Gauge One models are from one to two feet in length (300mm to 600mm); 50% longer than O gauge models and 50% shorter than “3 ½ inch”.