Abstract
In this paper, we study the real-time train assignment problem (RT-TAP) that arises from the unreliable arrival times of freight trains and the last-minute parking requests at railway yards. In the RT-TAP, the reassignment of trains to the yard is triggered every time a train arrives at the railway yard and needs to be assigned (event-based optimization). After introducing a problem formulation for the RT-TAP problem, we prove that RT-TAP is NP-Hard. In particular, the RT-TAP is modeled as a mixed integer program that strives to minimize the total weighted delay of trains. Because of its computational complexity and the time-critical nature of this problem, we introduce two real-time solution methods: (a) a problem-specific genetic algorithm (GA), (b) and a first-scheduled first-served (FSFS) heuristic. In small instances, we show that the GA returns a globally optimal solution which is identical to the solution of exact optimization methods. In larger problem instances, the heuristic approaches of FSFS and GA are tested at the Waalhaven Zuid railway yard in the Netherlands using two months of operational data. In the experimental results, the GA solutions reduce the average delays by more than 4 min compared to the solutions of the FSFS heuristic.
Highlights
Since the use of the first railway in the early 19th century, rail freight transportation has always played an important role in the transportation sector (Network Rail, 2016)
This study models the real-time train assignment problem (RT-track assignment problem (TAP)) and investigates real-time mathematical optimization techniques that aim to minimize the total delays of outbound trains at a railway yard
A survey on problem models and solution approaches with regards to the rescheduling in railway networks is developed by Fang (2015)
Summary
Since the use of the first railway in the early 19th century, rail freight transportation has always played an important role in the transportation sector (Network Rail, 2016). The large delays on the network and the high percentage of last-minute requests contribute to the complexity of assigning trains to tracks in real-time, further referred to as the RT-TAP problem. The large delays of trains, and the high percentage of trains scheduled with a small prior notice underscores the number of manual decisions made at railway yards To tackle this issue, this study models the RT-TAP and investigates real-time mathematical optimization techniques that aim to minimize the total delays of outbound trains at a railway yard. The output of the model provides an optimal assignment solution of trains to tracks that minimizes the total weighted delay on outbound trains from the railway yard.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Rail Transport Planning & Management
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.