i choose option B on the train. tuck n roll. instead of jumping out the back and landing on the tracks, i would roll out the train and keep the same speed and slow down. if you run out the back, you will leap and probably fall anyway since you cant be like wile coyote and run off a clif, stop and fall straight down. and how can you know you're running exactly 12mph? what if the train has no windows? how can you judge your speed? if it had windows, you could look outside and find something stationary to keep up with. and you only said the side doors were open, what if the back one was locked? there's alot to consider.