I've built what may be the longest railroad ever constructed in MCPE. Or close to it anyway. It connects two large cities. See it all in 6 minutes. Have fun!
MCPE achievements so far: 200,000 block railroad ride in 6 minutes: https://www.youtube.com/watch?v=chlCDKNDJ60
Night ride through New Chicago: https://www.youtube.com/watch?v=sO88BY03Ye4