Reducing Dwell Time: London Underground Central Line

Sponsor: Transport for London 13499945_10206417723941943_763365076_o
Sponsor Liaison: Eric Wright
Student Team: Jake Kelly, Dong Hyun (Danny) Ko, Laurie Mazza, Samantha E. Robinson
Abstract: Inconsistent and excessive dwell times often cause delays to underground metro systems. The goal of this project was to recommend solutions to minimize dwell times in the Central Line of the London Underground. The team conducted employee interviews, station observation, train observation, CCTV observation, and passenger surveys to more thoroughly understand the issue. Our team identified four system constraints that could be altered to encourage more efficient passenger behavior in order to reduce dwell times


TfL IQP Final Presentation (06_21_16)

Executive Summary

In an ideal underground rail system, every train would arrive and depart at its intended station without delay, but in reality, trains are behind schedule very frequently. In the London Underground in the past three years, passengers have experienced an average excess travel time of more than 4 minutes from their original scheduled journey (See Appendix G Figure 1; Transport for London, 2016g). Dwell time, the time from wheel stop to wheel start at a station, is one of the major factors that cause the train delays and diminishes the system’s ability to operate on schedule (Karekla & Tyler, 2012). Dwell time depends on system constraints, such as the station layouts and mechanical aspects of the train system, as well as passenger behavior. Excessive dwell times cause delays to singular trains, which can spread delays to the entire underground system (Wright, 2015).

The goal of this project is to recommend solutions to the current issue of high dwell times in the Central Line of the London Underground, a section of Transport for London (TfL). In order to form these solutions, the team identified the common factors that affect dwell time in terms of both system constraints and passenger behavior. First, the team became familiar with the system and the dwell time factors through initial employee interviews, including discussions with Templar House and the control room staff of the Central and Victoria Lines. Next, the team conducted station observation on the ten key stations, which were chosen due to their high dwell times. Train observation completed the first objective of identifying common factors through noting passenger flow and dwell times from within the trains during the morning peak time.

To narrow these factors into the final two key factors, the team studied the frequency and impact of factors through CCTV observation, a passenger survey, and frontline employee interviews. CCTV observation provided critical data on the frequency of platform crowding, types of problem passengers, and door reopening causes. The passenger survey conducted during peak and nonpeak hours lead to data compared between the different types of passengers: commuters, tourists, shoppers, and casual riders. Finally, interviews with train operators confirmed other data and suggested the importance of platform attendants.

The first key factor is uneven platform crowding that is extremely frequent during the morning peak hours as passengers crowd by the entrances and do not spread evenly along the platforms. Obstructed alighting and boarding is the second key factor because of its direct correlation to increasing dwell times as the doors remain open or reopen. These two key factors are caused by a combination of problem passengers and system constraints of the platform layout, information display, TfL employees, and the rolling stock. Updating or altering these system constraints could appease the currently high dwell times in the Central Line.

The suggestions on station platform layouts include foldable benches to provide more space for platform passenger flow, altering ventilation to encourage motion along the platforms, and decreasing train visibility from passageways to discourage rushing passengers. The information display options are updating current signage to create more informed passengers, creating a new passenger information display to provide more useful information, and including information on the platform floor such as way out arrows. One of the types of TfL employees directly related to dwell times, the Central Line train operators, commonly suggested to increase the presence of platform attendants that currently decrease dwell times during peak hours. Finally, rolling stock could be improved through more strategic handle placement to discourage passengers from blocking alighters, directional train doors to promote passenger flow through the trains, and an entirely new rolling stock with interconnected cars to cause less uneven train/platform crowding.

As this project concentrates on the non­technical factors associated with high dwell times, further research on these suggestions should be conducted. Further study should be completed on station­based passenger flow, communication between TfL employees, and increasing information for tourists in an interactive display. Studies on particularly complicated interchange stations like Bank/Monument would be beneficial as the passenger flow within these stations could be improved. Similarly, further research into the effects of updating technical aspects, such as the signalling system, may prove helpful for the Central Line in the future.