# Changes -- Scenario A (Sggmrs container wagon)

## v1.0.1 -- 2026-04-21

Provenance correction and rename. Content unchanged; metadata corrected.

- **Directory renamed:** `scenario-a-vtg-container/` -> `scenario-a-sggmrs-container/`.
  The scenario is anchored on the UIC wagon class (Sggmrs) rather than on
  any presumed operator. The Sggmrs(s) 90' class is commonly operated by
  multiple wagon keepers; this scenario uses the class generically against
  the BAV regulation.
- **corpus_source updated:** `vtg_fm_catalog_v2` -> `bav_fk_v12_2021`. The
  previous value implied a VTG catalogue as the source of the failure modes.
  The actual source is the publicly-published BAV *Fehlerkatalog* v12.0
  (2021), as correctly captured in `regulatory_anchors[].catalog`.
- **source updated:** `ai` -> `regulation`. Digital transcription of a
  published regulation is not AI enrichment; the source is the regulation
  itself. AI assistance in parsing/structuring does not make the source AI.
- **fleet_template_id updated:** `BENCH-VTG-SGGMRS-104` -> `BENCH-SGGMRS-104`.
- **Removed:** `entity.manufacturer_template` (was `"VTG"`);
  `entity.public_catalog_url` (operator-specific URL). These were
  assumption-based rather than source-derived.

The 297 failure-mode rows themselves are unchanged. `fm_uid` values are
stable. Old URLs under `/rail-corpus/v1/scenario-a-vtg-container/` and
`/corpus/transport/rail/v1/scenario-a-vtg-container/` are not preserved as
of this release; consumers should update their references to the new slug.

## v1.0.0 -- 2026-04-19

Initial Dublin release.

- **Asset:** Sggmrs(s) 90' container wagon (`ASSET-f1832bcabf20`)
- **Fleet template:** `BENCH-SGGMRS-104`
- **Failure modes:** 297 rows
- **corpus_source:** `bav_fk_v12_2021`
- **source:** `regulation`
- **Regulatory anchor coverage:** 8 chapter references across chapters
  1, 2, 3, 4, 5, 6, 7, 10

---

## Edition note -- structured vs. current

The 297 failure modes in this bundle were structured against the **BAV
Catalogue of irregularities, Version 12.0** (effective 01.01.2021) during
the original AI-assisted transcription pass. Internal provenance: X.01
(2 April 2026) assigned the `source_id` token `BAV-AVV-TBL-2021`; in this
bundle that corresponds to `BAV-FK-V12-2021`.

The **currently in-force edition** is **Version 18.0**, effective
01.01.2026, reference no. BAV-521.110.0-1/34/1 (English edition) /
BAV-521.110.0-1/34/2 (German edition), published by the Federal Office of
Transport (FOT) Safety Division. Public URL:
<https://www.bav.admin.ch/en/public-transport-safety>.

A spot comparison of Chapter 1 subsection numbering between v12.0 (2021)
and v18.0 (2026) shows **identical codes at the subsection level** -- e.g.
1.1.1 is present verbatim in both editions. The top-level chapter structure
is unchanged across editions.

A full subsection-level audit across the two editions has **not** been
performed for this bundle. That audit, and the broader question of how to
preserve a stable failure-mode identity across catalog editions, is tracked
as **WI-163** and is scheduled for v1.1 of the Open Rail Corpus.

## Community review layer (planned)

A community-review trust layer is planned for a later release. The intent
is that individual failure modes, once reviewed and approved by community
reviewers (Rail SIG participants, operators, regulators, reliability
practitioners), graduate to a higher trust tier. The v1.0.x releases
represent the transcribed-from-regulation tier; a future release will
introduce a community-reviewed tier, and subsequent releases may introduce
operator-validated and actuarially-calibrated tiers. The trust tier of each
failure mode will be machine-readable. Design details pending community
feedback at RAM 2026 Dublin and subsequent Rail SIG conversations.

## Asset-class note

This scenario is served under the path `scenario-a-sggmrs-container/`. An
earlier internal draft used the path `scenario-a-vtg-tank/` (referencing a
chemical tank wagon). The pivot to a container wagon was a deliberate
choice to use a universally-recognised, neutral-cargo freight asset as the
scenario carrier. The regulatory structure (BAV Catalogue of
irregularities) applies to both asset classes; the demonstration of corpus
structure is identical in substance.

## Identifier derivation

`fm_uid` values are computed deterministically at bundle assembly time as
`FM-<sha1(entity_id | rds_component | failure_mode)[0:12]>`. Re-running the
assembly against identical source data produces identical UIDs, supporting
stable inbound references.

## Open question (WI-163): eternal FM identity across catalog editions

The current `fm_uid` derivation is sensitive to regulatory subsection
renumbering. If the BAV renumbers a subsection in a future edition, the
`fm_uid` for that failure mode would change under today's scheme, even
when the underlying failure mechanism is identical.

The doctrine question -- how to preserve a stable failure-mode identity
across regulatory-catalog editions -- is being actively scoped as WI-163
and will be addressed in v1.1 of the Open Rail Corpus. Feedback is welcomed
at RAM 2026 Dublin and subsequently via the Rail SIG for Intelligent Asset
Management.

Candidate approaches under consideration include mechanism-first hashing,
SKOS-style supersession relations, and a catalog-version-scoped identity
layer with cross-version equivalence mappings.