The Rangoon to Mandalay express trains are a pretty comfortable and in fact relatively fast and punctual option for travel between these cities. Pretty bumpy in places, that's true, but much more comfortable than cramped buses and infinitely more of a genuine Burmese experience than any flight. In fact, the train ride is a highly recommended experience, over the old British-built colonial railway. Most Rangoon-Mandalay trains were rescheduled to run by day rather than overnight in 2006 when the government moved the capital to Naypyitaw, but switched back to being mostly overnight from January 2012. The timetable below comes from confirmed data from 2014, still in force in 2015, beware of a number of Burmese websites showing out-of-date timetables.