Are there limits on the railroads' responsibilities towards passengers?
There are reasonable limits, yes. The railroad is not required to absolutely guarantee safety in any and all circumstances - highly unpredictable circumstances or accidents may fall outside of railroad responsibility. Passengers also must conduct themselves reasonably, by following railroad safety rules and not exposing themselves to dangerous conditions while the safe alternatives are accessible. The specifics are highly context-dependent, but circumstances entirely beyond railroad control and which would not have been prevented through greater safety measures are more likely to fall outside of railroad responsibility.