Double deck trains are claimed to be more energy efficient, and may have a lower operating cost per passenger. A bi - level car may carry up to about twice as many as a normal car, if structure and loading gauges permit, without requiring double the weight to pull or material to build. However, a bi - level train may take longer to exchange passengers at each station, since more people will enter and exit from each car. The increased dwell time makes them most popular on long-distance routes which make fewer stops (and may be popular with passengers for offering a better view).
