Metro Light Rail has used various "consists," or train configurations, since service began in late 2008. Thankfully, the dreaded "unitrains" with only one car seem to be a thing of the past. They reduced power consumption and costs but took an unacceptable toll in terms of passenger comfort and light rail's image. Now, the question is when to use two-car trains, the most common configuration, or three-car trains, the longest configuration permitted by station design.

Three-car trains are generally seen during the morning rush hour. At that time, they're enormously helpful in dealing with the crush of Central High School students who pack trains in both directions before disembarking at Campbell. Maybe some three-car trains run during the mid-afternoon when high school classes end, but three-car trains are rarely seen during the evening rush hour around 5 PM, even when they would be extraordinarily helpful in dealing with the combined load of commuters and Diamondbacks fans.

When Diamondbacks home games end, however, three-car trains are often waiting to take passengers home. In a way this makes sense. Spectators tend to arrive gradually but leave in a sudden rush when games are over. The downside is that it's easier to leave Downtown than it is to arrive in Downtown, reinforcing the Phoenix Police Department's practice of directing car traffic coming out of Downtown garages in a way that moves vehicles toward freeways as fast as possible.

The best way to address all of these issues is to run more three-car trains during the evening rush hour. These longer trains would make it easier for light rail to accommodate both its regular passengers and its occasional users headed Downtown to special events. In addition, having as many three-car trains before events as after events would introduce a level of balance that makes it equally appealing to eat early before a game or to linger Downtown after the event has concluded.