Nobody has measured light speed on a moving train, neither moving away or towards the light source. Is light, photons, even electromagnetic waves?
Does Maxwell's Equations apply to light, moving photons?
Why is time speed equal to light speed? A clock face not updating because you are moving at light speed away from it, does not mean time has stopped. Even if time has stopped, that does not mean time is at light speed either. You may catch up with the photons from the clock face and even see images of the clock hands reversing as you pass photons that was emitted before (as you travel faster that light speed supposedly), but your time is still forward. You experience time in the same way. And so does the clock, as it tick on irrespective of what you are doing. Time do not stop, as you travel at light speed. Not for you nor for any observer.
So, what the fuck.
