Bi-Weekly Talk: Stephan Zieger: The Dial-a-Ride Problem in Railways
Wednesday, April 21, 2021, 10:30am
Location: Online Session
Speaker: Stephan Zieger
The shift towards greater urbanisation in several countries has led to less emphasis being placed on railway lines in rural areas.
In some cases, it is very difficult to sustain a railway service on these lines that is both demand-oriented and economically viable.
As a result, services on many lines have been limited or even discontinued.
One way to make rural railway lines more attractive again and to operate them with an even stronger passenger-focus is to use small automated rail vehicles.
This paper examines how an operation in such a scenario can be implemented.
For this purpose, a mathematical optimisation program is presented which solves the resulting on-demand offline scheduling problem.
Constraints such as time windows, vehicle capacities or occupation times of railway sections have to be taken into account.
The number of constraints quickly leads to large problem sizes, which can be reduced by pre-processing techniques -- at least to some extent.
The implementation and possible reductions of the problem are described in detail.
The reductions have a moderate influence in a sensitivity analysis and can significantly contribute to enhance the solvability of the problem.
The mathematical optimisation program is applied exemplarily to a regional line and yields an optimal schedule for smaller instances.