The 5000-series cars — similar to those seen in the New York City subway — have wide aisles and provide more standing room during rush hour but are unpopular with some riders, who do not like getting their feet stepped on while they are seated or being eye level with the buttocks of standing passengers. These cars use more power than older cars, and the Blue Line doesn’t have enough power to run only 5000-series cars during the rush hour. But using a few provides extra capacity, the CTA said.