The speaker for the Wednesday, 21 October 2020 INFORMS Railway Applications Section (RAS) International Webinar Speaker Series was C. Tyler Dick, RailTEC Lecturer and Principal Railway Research Engineer. Over 80 online participants listened as Tyler presented “Network Efficiency Cycle: Quantifying Yard and Mainline Railway Capacity and Performance Connections”. His presentation summarized research to understand and quantify relationships between the capacity and performance of both classification yards and mainlines, these disparate yet complementary facilities. This was the fourth online webinar in the RAS International Webinar Speaker Series which was organized to feature operations research and advanced analytics applications and good practices in the railway industry with speakers from both academia and industry. Click here to see a list of webinar speakers and find the link to a video recording of Tyler’s presentation.