The Road to Incremental Allocation & Incremental Planning Content and Potential

This document summarizes how SICS envision “The road to Incremental Allocation and Incremental Planning” and is in essence a more detailed description of what SICS formulated as ”the road to the dynamic train plan” in the project Den Dynamiska TågPlanen (The Dynamic Train Plan). Moreover, this document summarizes some of the results and tests that have been performed in the projects Tågplan 2015 (Train Plan 2015) and Marackasen (The Maraca). These results support the reasoning behind the first steps of the road to Incremental Allocation and Incremental Planning. Introduction At Trafikverket (the Swedish Transport Administration), there are several related, ongoing projects and initiatives collectively referred to as Incremental Allocation, Successiv tilldelning (ST) in Swedish, and Incremental Allocation, Successiv planering (SP). They spring from a series of research projects carried out at SICS (Swedish Institute of Computer Science) from the year 2005 and onwards. The research was initially funded by Banverket (the Swedish Rail Administration) and then by the newly formed government agency Trafikverket which took over the responsibilities of Banverket in 2010. The purpose of ST and SP at Trafikverket is to develop and implement a process founded on a new methodology for planning railway capacity. This methodology aims at enabling more efficient use of existing capacity and resources. A corner stone in the new methodology is the distinction between delivery commitments on the one hand, and production on the other hand. The relationship between the two is also central to the methodology: Delivery commitments define the goals for the production. With this in mind, the purpose of a planning activity depends on in what part of the process it is carried out: Long term planning aims at establishing the delivery commitments while production planning aims at fulfilling the commitments. This document consists of two parts. The first describes a number of concrete steps that we as researchers believe will ensure a smooth transition from the current planning approach towards the planning process that Trafikverket aim for in ST and SP. The second part of the document describes some of the benefits of adopting the new approach using some illustrative examples. The steps towards the new planning approach The following steps, or stages, towards the new planning approach are based on the assumption that it is not wise to introduce too many big changes at the same time. Big values are at stake in the train plan process and every change needs to be subject to quality assurance. It is important that everyone involved will have the chance to adapt to each change and thereby feel secure in his/her own new role before the next change is introduced. The stages below are numbered in the order in which we, as researchers, assume they will be implemented. Stage 0 Single out the delivery commitments from the production specifics in the train plan. The train plan (tågplanen in Swedish), i.e. the yearly plan that is produced in today’s process, is essentially a production plan. This stage involves making all relevant parties aware of the distinction between delivery commitments and production specific details in the train plan. Once this stage has been implemented, the railway undertakings (RU:s) will receive a set of delivery commitments as reply to their application instead of the detailed train paths. The process of constructing the yearly train plan, the so called train plan process or long term process, is not changed at this initial stage, nor is the ad hoc process that follows the train plan process. This is why we call it Stage 0 instead of Stage 1: concepts are introduced, but no changes to the main processes need to be made. By talking about delivery commitments instead of the train plan, especially in TRAV (the contract: Trafikeringsavtal), the foundation for the following steps is created. The change introduced at this stage affects the RU:s, and it is very important to gain approval from them for the idea of separating the delivery commitments from the production specifics. Stage 1 Provided that Stage 0 has been implemented, Stage 1 assumes a process that is essentially identical to the current one, but with one major difference: Instead of setting the production specifics in stone at the end of the annual capacity allocation process, settle only the delivery commitments. In today’s process, when the annual capacity allocation process is finished in mid-September and the contracts between Trafikverket and the RU:s are being written, the train plan has traditionally been viewed as part of the contract. The train plan is a very detailed document, and it has been interpreted as a production plan by the RU:s and Trafikverket alike. Refraining from fixating the production specifics at the end of the train plan process enables the production plan to be re-optimized at any time during the ad hoc process. This results in the following advantages: a. The yearly train plan can be divided into daily plans which can be optimized separately whenever a need to do so arises.  Every change to a particular day should improve the plan for that day, otherwise there is no point in making the change in question. b. A final optimization of the plan for the upcoming day can be carried out before it is handed over to the dispatchers.  The ultimate goal is to hand over the most correct plan possible, where correct in this context means two things: (1) The plan corresponds to the way in which the trains will in practice be dispatched in the event of no disruptions, and (2) The plan is optimized with respect to its ability to fulfill the delivery commitments, even for the case when not all things go as planned. Note that point number two above in essence says that the plan should be robust. c. The feedback loop between dispatchers and timetable constructors will be shortened.  Trafikverket will have the possibility to modify the production plan immediately after evaluating its actual performance quality during operations, which allows for much better feed-back loops and learning possibilities. d. Track possessions (downtime required for maintenance) may cause changes to train paths as long as the delivery commitments are respected.  The chance of finding longer, continuous periods suitable for maintenance increases. The train plan must not contain any resource conflicts in the current process, and this requirement does not change with the implementation of this stage. This stage gives Trafikverket the opportunity to optimize the plan, but also poses no requirements on them to do so. If the plan is never optimized, it simply has the same quality as in Stage 0. Stage 1 is thus backward compatible with the process of today in this regard. Implementing this stage, Trafikverket abandon the rule that says that train paths cannot be modified after the train plan process has ended. During the ad hoc process, the short term planners will now be free to modify train paths as long as they still respect the delivery commitments. The production plan must be conflict free after each change to it, so that everyone in the process is sure that it is still a feasible plan. The difference from the previous approach is that every day can have a different timetable for the same train (as long as the same delivery commitments are respected). Stage 2 Allow a train to have different train paths for different days already in the long term process, i.e., in the yearly plan In the previous stage, once the train plan process (long term process) is over and the train plan has been constructed, the short term planners are free to optimize the production plan as long as all the delivery commitments are respected. Before any such optimization takes place, a train will initially, in the train plan, have the same train path every day it runs. This is an artifact of the manual procedures involved in constructing the train plan in the long term process . After Stage 1 has been implemented, it no longer makes sense to require that the long term planners construct a train plan where each train has the exact same train path every day it runs: That property will be violated as soon as different days are optimized separately by the short term planners anyway. In Stage 2, the long term planners will be encouraged to allow trains to adjust to the different days they run already during the construction phase. In the most extreme case (point 1a, Stage 1), every day can be viewed as If it has its unique variants of all trains. That level of detail is not yet possible to manage in the long term process. The planners are at this stage not expected to treat every single day separately, but keep their eyes and minds open to the possibility of using capacity more efficiently by splitting some trains into two or three variants. When this stage has been implemented, a train will not automatically have the same train path every day it runs when the long term process is finished. If efficiently handled, variants free up capacity in the train plan. This capacity is a hidden asset today since it is not immediately visible. Some of it is naturally exposed when the individual days in the train plan are singled out, and today capacity revealed in such a way is indeed used by the dispatchers, albeit in an ad hoc fashion. However, by identifying it already in the long term process, it can be used to increase the general overall ability to deliver, pave way for more efficient train paths, enable more efficiently planned track possessions, or to make room for more trains. The notion of variants is not foreign to the process of today, but the administration around the procedure is rather stilted and every such variant becomes a separate train with a unique train number. Moreover, variant creation today is completely manual: Situations where capacity can be utilized more efficiently if variants are introduced