This report presents the results of a cognitive task analysis (CTA) that examined the cognitive and collaborative demands placed on conductors, as well as the knowledge and skills that experienced conductors have developed that enable them to operate trains safely and efficiently. A secondary aim of the CTA was to understand the implications of the Rail Safety Improvement Act (RSIA) of 2008 regarding the role of the freight conductor, specifically the mandate for conductor certification and implementation of positive train control (PTC). Data was collected through a combination of field observations, phone interviews, and onsite focus group sessions with experienced conductors, locomotive engineers, trainers, and training managers. A primary finding is that conductors and locomotive engineers operate as a joint cognitive system (Woods and Hollnagel, 2006). They not only work together to monitor the operating environment outside the locomotive, they also collaborate in planning activities, problem solving, and identifying and mitigating potential risk. Although the present CTA does not directly address the issue of how new technologies, such as PTC, are likely to impact the role of conductors in the future, the CTA results do identify multiple ways in which conductors contribute to safe and efficient train operation. As new PTC technologies are introduced, it will be important to assess their impact on the various functions conductors perform in support of safe and efficient train operation, as specified in this report. The CTA also uncovered a variety of knowledge and skills that distinguish experienced conductors from less experienced ones. These findings suggest an opportunity to potentially accelerate building conductor expertise through more systematic training opportunities (both on the job and in locomotive cab simulators). The report concludes with open questions and future research needs as yet uncovered by the CTA.