It’s all about the timing

Fixed guideway transit operations planning and scheduling is as complex as it sounds. Nevertheless, a great deal can often be accomplished with even the smallest change.

Operational timing conflicts can cause numerous complications including ineffective network convergence points or inability to meet capacity demands. It requires an honest and sometimes painstaking look at all of the available scheduling options to prevent such issues from occurring. Doing so can help prevent future costs such as building new infrastructure or purchasing new transitvehicles. While it can be a meticulous process to configure and reconfigure timetables, it is usually worth the effort to extract the most out of what is available.

Horse before the cart

Operations and scheduling are often no more than afterthoughts considered, at best, late in the concept design phase of a project, at worst during the detailed design phase. But, paying attention to how fixed guideway services might be run in the future, including service frequency, potential maintenance facility location impacts, and the effects of converging with services from other lines will help embed flexibility into a project.

Transit organizations would benefit from considering operations earlier in their project planning, and by doing so, uncovering possible underlying issues with system design sooner. Adjusting a design in the early stages of a project will cost far less than making adjustments to design and scheduling after construction is complete and the system is in operation.

Steer Davies Gleave believes in building this type of operational analysis into every study we do. Our work on the City of Edmonton’s Northwest LRT Concept Plan involved analyzing the scheduling of multiple services through a tunnel, as well as overall travel time options and intersection analysis. The study gave clear indications about how the line may function when it becomes operational. Future stages of work can continue to build on and refine this information as more details become available.

Over time, transit services will inevitably undergo some transformation to meet passenger demand and serve new areas. Planning ahead is therefore essential, as constantly evolving operations can help transit agencies avoid sudden, costly upgrades.

Understanding the problem

To find an effective solution to fixed guideway operations and scheduling issues, it is essential to have an extensive understanding of the root problem causing them. Occasionally, a poorly thought out alignment design can limit how successfully a system will operate. The symptoms of poor design can manifest themselves differently; for example, the system could fail to meet passenger demand. To redesign a schedule that truly complements the available infrastructure, it is essential to know the finer details of certain designs, and by doing so, be able to predict their possible ramifications.

It is also a matter of finding an equilibrium between competing factors affected by minor changes to schedules. Issues ranging from capacity shortfalls and platform crowding to fleet maintenance scheduling or modifications to operator agreements can all potentially be solved with careful adjustment of timetables.

SDG has solved a range of operational challenges for transit agencies, such as Sound Transit in Seattle which contributed to reducing the need for costly interventions. Even with network bottlenecks or platform restrictions, simple changes, such as redistributing station dwell times or reducing slack in the timetable can potentially allow for quick improvement.

Breaking down the issues at hand to find the right balance can be challenging, but the payoff can be incredibly beneficial.