Through-Running Regional Rail (2026)
Chapter: Introduction
TRANSIT COOPERATIVE RESEARCH PROGRAM
CONTENTS
Recommended Changes to the TCQSM
Through-Running Regional Rail
As part of TCRP Project A-47, “Transit Capacity and Quality of Service Manual, Fourth Edition,” the research team conducted a series of small research tasks to develop new content for the manual. This TCRP research results digest (RRD) is one of 12 presenting the results of these research tasks. In contrast to traditional peak-period, peak-direction commuter rail service, through-running regional rail provides bidirectional, all-day, relatively frequent service through an urban core that can serve multiple trip purposes. This RRD provides insights into how a through-running regional rail systemʼs capacity is affected by its physical and operational characteristics, service reliability, tolerance for train delays, and other factors. Armando Pigman and Foster Nichols authored this RRD, both of WSP USA Inc. The responsible staff officer is Dianne Schwager. Links to the 12 RRDs and TCRP Web-Only Document 79: Developing the Fourth Edition of the Transit Capacity and Quality of Service Manual are available on the catalog page for TCRP Research Report 262: Transit Capacity and Quality of Service Manual, Fourth Edition (https://doi.org/10.17226/29449).
INTRODUCTION
This small research task addresses the growing interest in the potential to transform traditional commuter rail systems into regional rail systems with more transit-like characteristics. This interest preceded the COVID pandemic but has been amplified and reinforced by observed changes in urban and suburban travel behavior following the pandemic, such as remote work and reduced commuting, less concentration of peak travel to and from 9-to-5 jobs at workplaces within central business districts (CBDs), and more dispersed travel patterns. These changes have resulted in travel in both directions and at all times of day, rather than being highly concentrated during the weekday a.m. and p.m. peaks (to and from CBDs, respectively) (Lewis and Shirky 2025). The idea of introducing through-running regional rail service is being considered in Chicago; Washington, DC; New York; Boston; Los Angeles; Toronto; and other North American cities as a means of moving beyond traditional commuter rail models and adopting transit-style services that offer bidirectional, frequent, and purpose-varied travel that passes through the urban core. These efforts reflect a shift in travel patterns in a post-COVID world, and services recognize that the legacy model of suburb-to-city commuting may need to evolve into a more flexible, metropolitan-oriented transit approach.
Research Task Objective
The objective of this research was to enable transportation planners and sponsors of passenger rail service to evaluate through-running relative to other modes of operation and to develop information about the factors that drive system capacity for through-running operations. The research was intended to provide insights into how the capacity of a through-running regional rail system is affected by assumptions about its physical and operational characteristics, service reliability and tolerance for train delays, rail passengersʼ needs and desires, and the system characteristics that compel travelers to ride trains. The researchers investigated both opportunities to maximize capacity and challenges with respect to implementing through-running operations. This includes examining the technical, operational, and physical barriers that may limit or
