The many possible combinations of crew tasks, inconsistent train schedules, and constantly changing crew data make scheduling railway crew members a complex task. The Dutch Railways, Nederlandse Spoorwegen (NS), found that moving to computerized schedules was not easy, either. Tests of software that created the schedules on its own were disappointing because the software could not adapt easily to changing circumstances or manage the vast number of possible crew combinations. The human planners also found they could not tinker with the software's variables in mid- process to try alternatives.

Since 1996, the railroad has used software that relies heavily on artificial intelligence (AI) technology. The combination of human intervention and computer assistance is powerful. Without computers, twenty-four planners working full-time for six to twelve months were needed to schedule 5,000 engineers and train guards. With the AI software, the same...