Much less time than most people expect. When the train, light-rail, or bus that hurt you is operated by a public transit agency, your claim is a claim against the government — and California generally requires a formal government claim to be filed within about six months of the injury, far shorter than the usual two-year window for an ordinary injury case.
That short deadline is the single most important issue in a transit case. Missing it can bar the claim entirely, regardless of how strong it otherwise is. Because it can be hard to know at first whether a public entity is involved — many light-rail and commuter systems are run by government agencies — it is important to find out quickly.
This is why getting advice early matters so much in train and light-rail cases. A prompt review can identify whether a government agency is a party, confirm the exact deadline that applies, and make sure the required notice is filed correctly and on time.