Actual working hours of employees vary widely, especially in the transportation industry. We developed a tool, the RAS (Representation and Analysis Software), to ease the assessment of such irregular hours and the transfer of existing knowledge of proper schedule design to the problem of irregular hours. This article discusses several critical design questions that were addressed during software development in order for it to assess irregular work patterns, including the (1) importance, in spite of a lack of established definitions, of basic concepts like, e.g., night shift, (2) difficulty of modeling and adapting existing knowledge on proper design, and (3) large number of analytical methods and additional data beyond company schedule that are necessary to meet the needs of various research groups. This article describes how the RAS addresses these three issues by illustrating its application to the work schedule of a train driver involved in the Hinton train disaster.