IEEE 1474 vs IEC 62290
US CBTC specifications increasingly cite both standards, and for good reason: they do not overlap. IEEE 1474 tells a vendor how well the system must perform. IEC 62290 tells it what the system must be. Citing only one leaves a gap a bidder can price into.
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What's inside
- Six-dimension comparison: origin, scope, GoA treatment, safety specification, procurement focus, and use in US projects.
- The one-sentence distinction that settles most specification arguments.
- How the two standards are combined in current US practice, with named agency examples.
- Where each standard belongs in an RFP — performance clauses vs functional architecture clauses.
Why both, and not one
The short version, and the line worth pinning above a specification desk:
IEEE 1474 says “the system must achieve 5.5-minute headways with 99.5% availability.” IEC 62290 says “the system must execute ATP at SIL 4 and support GoA 2.” Both are necessary during procurement.
European operators — RATP, Deutsche Bahn, Île-de-France Mobilités — have specified IEC 62290 compliance and GoA level contractually for over a decade, which pushed vendors to build IEC-aligned products by default. US agencies came from the opposite direction, relying on IEEE 1474 and custom specifications. The result is that most US agencies now receive IEC 62290-compliant systems whether or not they asked for them — NYC MTA's B Division procurement did not cite IEC 62290 and got compliant systems anyway, because that is what vendors build. LA Metro's Purple Line Phase 4 specified both explicitly. That is the direction of travel.
Sources & method
Adapted from Communications-Based Train Control, Volume 1, Chapter 2 (Table 2.2), by Chunjun (Francisco) Wang. Standards positions reflect IEEE 1474 and the IEC 62290 series including amendments through 2025. Agency examples are drawn from published procurement documents.