Train going 100 mph, and me running on the train 10 mph the same direction, I am not moving 110 mph from the perspactive of the ground. I am moving a little bit slower.



In relation to a fixed point on the ground you would indeed be going 110 mph, until you ran out of train.

If two automobiles are traveling toward each other at 40 mph their CLOSING RATE is 80mph.

The point of that being the closing rate being higher than the speed of light gives a higher energy on collision than hitting a stationary target at the speed of light.