What is the ruling on performing the obligatory prayer on a train for a traveler who is permitted to shorten prayers (qasr) and fears missing the prayer's prescribed time?

A traveler on a train should delay the prayer if he knows he will disembark before its time expires, and he should not pray it inside the train if he cannot fulfill its pillars and conditions. However, if he will disembark after the time has expired, he should pray it inside the train according to his ability, standing, bowing, and prostrating if possible. If he is unable, he should gesticulate, and he should strive to determine the Qiblah. There is no difference in this regard between long and short journeys.