ADR-002: Generic railway schema (not Tube-hardcoded core)

• Status: Accepted
• Date: 2026-07-17

Context

Open question #2: Tube-specific vs generic railway concepts in the core model.

Decision

Core schema uses generic railway entities (system, line, branch, direction, station, section, etc.). London Underground terminology and IDs live in a London network profile, not in core type names.

Consequences

Slightly more abstraction up front; avoids painful migrations when expanding. UI may still say “line” in London English.

Links: ../architecture/journey-segmentation-model.md; ../research/06-railway-journey-model.md.