INTRO: Automation of conflict resolution over wide geographical areas can speed up the timetable and train service planning process dramatically. The time to optimise infrastructure capacity, trains and crews to match business objectives can be cut from months to hours
BYLINE: Tom A Greaves CEng MIMechE MCIT
Director, VST ComrecoRail
Historically, train schedules have been drafted by timetable specialists with long experience of the customs and practices in planning services for a specific geographical area. This has resulted in scheduling becoming one of the rail industry’s last ’craft’ activities.
While fundamental inputs such as traction performance are unlikely to change, the need for more responsiveness and geographical awareness are increasing rapidly. Fortunately, the elusive goal of semi-automated train scheduling is at last within our grasp.
This completely alters the trade-off between management’s desire to optimise the timetable and the substantial costs of plan-building using traditional methods, which are very time-consuming. Typically, timetables are rebuilt and modified twice yearly to accommodate minor changes. Where traffic stability is present, the period expands from one to five years.
Total replacement of services in the form of a new core timetable is a relatively rare event, and has almost invariably been associated with new investment, particularly electrification. Initial operating problems, leading to a period of fine-tuning the timetable, are commonplace owing to the sheer complexity of the manual process, which is prone to error.
Managers have often sought to use the calculating ability of computers to simplify this process and reduce their dependence on specialist train planners. But the essential grasp of geographical and operational knowledge required has prevented this from happening in all but the simplest cases, such as a metro line.
The time required for a typical timetable build process is normally in excess of 12 months. On a large national network, it is managed in geographical segments using individual planners knowledgeable about specific routes or areas. The service plan usually gives priority to express passenger trains, followed by local trains, then by mail and parcels, and finally by freight trains.
Despite many disagreements, a timetable is eventually produced which meets many aspirations of the business managers but falls far short of total satisfaction. Total planning time for an international train service in continental Europe, for example, is rarely less than two years and often in excess of three. The failure to harmonise timetables, leading to long delays at frontier yards, has been identified as an important factor in rail’s inability to compete successfully with road for international freight.
The urgent need for a highly proactive rail product offer can only be achieved by computer-based train planning and infrastructure evaluation processes. Manual processes are too expensive, too slow, and often inaccu-rate. Software to perform these functions has been available for some years, but they are last generation products, diverse in design and application, lacking both system integration and the ability to exchange data freely with other systems.
Fragmentation and the privatisation of British Rail in the mid 1990s put pressure on Railtrack to improve the timetable planning process, for which it remains responsible as the infrastructure provider. Some 30 train operators now compete for access to the network, and thus contribute to the generation of a national timetable held on a single database. This covers the whole of Railtrack’s 16666route-km, including some of the busiest inter-city and commuter lines in the world.
A totally integrated systems approach to providing a responsive business-focused operations planning process was required, and this has been developed over the past two years by VST ComrecoRail. Using the TrainPlan System, Railtrack’s timetable planning teams now have the ability to reschedule trains within a matter of hours, using technology which allows conflict-free revisions to be made in real time if required.
Train planning complexities
The fundamental objective of the train planning process is to find an acceptable path for all the trains which operators want to run through the network. Where that is not possible, the best compromise is sought in the short term which reconciles:
