What actually happened.

TIDES is an open standard for historical operations data: where vehicles went, who boarded and what was paid.

GTFS describes the plan and GTFS-Realtime the present. For the past there was no shared format, so every vendor's export looked different.

TIDES defines common tables for that history. TransitAI Core standardizes its cleaned data to match, so records from any vendor end up looking the same in the Silver layer.