In the train-embankment thought experiment described by Einstein in his "public" version of STR, he says the following: “Hence the observer will see the beam of light emitted from B [the front of the train] earlier than he will see that emitted from A [the rear of the train]. Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B [front of train] took place earlier than the lightning flash A [rear of train].” [ REF: https://en.wikisource.org/wiki/Relativity:_The_Special_and_General_Theory/Part_I ] I take issue with the phrase "must ... come to the conclusion." I actually think it very unlikely that the passenger would jump to that conclusion. Here is my reasoning: The only way to "see" a difference in the arrival-time of these two light beams would be to detect it using sophisticated machinery. For example, assuming a 20-meter long train car traveling at 120 kph, the difference in arrival time would be around 200 trillionths of a second (if my calculations are correct). Those with access to such sophisticated machinery would already be quite aware of the hazards in jumping to any conclusion about the "real" time-origin of the two beams, especially knowing all the debates in physics that have been raging about exactly such problems. Thus, the passenger, having "observed" the phenomena on a measuring-device, would probably come up with any number of theories to explain the findings, and would withhold judgment until more definitive evidence was uncovered. Note also that anyone able to measure such beam arrival-times would probably also be able to detect a red- or blue-shift in the frequency of such light beams. Would it not be true that, in Einstein's scenario, there would be a blue-shift in the "B" (front) beam and a red-shift in the "A" (rear) beam? If so, the sophisticated passenger would have stronger (but not definitive) evidence that s/he was not standing still relative to A and B, but was actually in an inertial frame moving toward B and away from A. This color-shift example casts even more doubt on the claim that the passenger would be forced to make a specific conclusion from the observed phenomena.