Record Layouts: Fields, Positions, and Validation
Understanding fixed positions and how edits validate alignment and content.
Updated 8/14/2025 · 1 min read
Fixed-width discipline
Metro 2® uses fixed-width fields with defined positions and allowable values. Even small misalignments can cascade into failed validations, so consistent padding, date formats, and numeric handling are critical.
Character vs. packed
Choose one representation for the entire file. Coordinate with CRAs about expected formats in test and production environments.
Appendage sequencing
Attach optional segments in the correct order and only when applicable. Emit the segment identifier and blank-fill the rest only if the CRA explicitly requires it for your configuration.
Last updated
8/14/2025