Beginners Ask Trains A closer look at F scale

A closer look at F scale

By Cody Grivno | July 16, 2025

It’s the National Model Railroad Association’s designation for 1:20.3-proportion trains on 45mm large scale track

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Color photo of two steam locomotives on scenicked model railroad.
Two-truck Shay No. 4 (left) and Porter 0-4-0 switcher No. 1 are Bachmann models that were detailed and custom decorated for the F scale Chester & Beckett, featured in Great Model Railroads 2018. The scale is sometimes referred to as 1:20.32 proportion. Photo by Doug Scott and Mike Tylick

Q: In the September 2022 issue of Model Railroader, Mike Tylick wrote “Add a gated crossing to your layout.” On page 36, there is an image of a gate that he built for the F scale Chester & Beckett RR. What is F scale? — via email

A: The Chester & Beckett RR was featured in Great Model Railroads 2018. The 16 x 20-foot sectional model railroad was built by Steve Morrill, John Sacerdote, Doug Scott, and Mike Tylick. In the article, it said, “F scale is the National Model Railroad Association’s designation for 1:20.3-proportion trains on 45mm ‘large scale’ track.”

Using that information as a lead, I visited the NMRA’s website. In General Standard Scales (S-1.2) it notes that F scale is .591″, or 15mm, to the foot. You may also see it referred to as 1:20.32 proportion. The minimum track gauge is 2.783″ and the maximum gauge is 2.845″. In the notes section of S-1.2, it states, “Proto:20.32 and F are the same other than flange depth.”

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