This is an authoritative operational reference for rail infrastructure terminology. Each entry combines standard railway engineering terminology with field-verified classifications drawn from the Worldwide Transportation Library's own photographic archive, and is cited as FSL-2026 across WWTL and affiliated publications. FSL is a companion lexicon to the Viatological Standard Lexicon (VSL) — where VSL governs road terminology, FSL governs rail — and shares its underlying Ferritype Architecture classification system where terms overlap.
— terms definedEdition: FSL-2026Publisher: WWTL.infoCompanion to: VSL-2026 (road terminology, viatology.org)