Quantum optimised train schedules

Planning and operation of public rail transport networks involves a complex balance of passenger service, infrastructure management for feasible and safe operations, and network resilience to disruption. To effectively meet these objectives, fast and high-quality optimisations are needed.

Mathematical optimisation is integral to strategic, tactical, and operational decisions; this includes line planning of train routes and frequencies, planning schedules that are feasible and robust with available infrastructure, crew management, and train timetable rescheduling in response to delays. Typically these optimisation problems are intractable for exact solvers on the scale of practical networks; approximate optimisers are used to provide faster solutions but with lower solution quality.

Using quantum computers, Q-CTRL aims to improve the quality of solutions obtained rapidly; a few percent improvement in quality can correspond to substantial improvements in transit time, robustness to delays, and reductions in operating costs and emissions.

Q-CTRL is working with the Department for Transport (DfT) and Network Rail to address train schedule optimisation both for large-scale rail networks, and for detailed station routing. Q-CTRL will design and deploy a quantum algorithm to perform train schedule optimisation on Oxford Quantum Circuits (OQC) quantum computers. The combination of Q-CTRL's world-leading expertise in quantum solution design and infrastructure software to maximise hardware performance, together with OQC's state-of-the-art quantum computers, will provide prototype train scheduling solutions, and provide an accelerated roadmap to deliver enhanced solutions from quantum computers.