 | It has been suggested that List of rail transport modelling scale standards be merged into this article. (Discuss) Proposed since July 2024. |
 | This article includes a list of general references, but it lacks sufficient corresponding inline citations. (July 2014) |
Rail transport modelling uses a variety of scales (ratio between the real world and the model) to ensure scale models look correct when placed next to each other. Model railway scales are standardized worldwide by many organizations and hobbyist groups. Some of the scales are recognized globally, while others are less widespread and, in many cases, virtually unknown outside their circle of origin. Scales may be expressed as a numeric ratio (e.g. 1/87 or 1:87) or as letters defined in rail transport modelling standards (e.g. HO, OO, N, O, G, TT and Z.) The majority of commercial model railway equipment manufacturers base their offerings on Normen Europäischer Modellbahnen (NEM) or National Model Railroad Association (NMRA) standards in most popular scales.