Redesign of a Non-electrified Urban Railway Line with Hydrogen-Fuelled Trains

The passenger rail transportation system is of strategic importance to the decarbonization of the transportation sector. The use of green hydrogen is an environmentally sustainable option where highly polluting diesel trains currently operate on non-electrified rail lines. This paper proposes a novel adaptive power flow management strategy for urban railway trains powered by a hydrogen fuel cell stack and electrochemical batteries. The fuel cell stack is not dynamically controlled as usual, but it operates in on-off conditions to improve its overall efficiency. It always operates at the maximum efficiency operating point when it provides electrical power (on state) without following the load power variations. Furthermore, the state of the fuel cell stack depends on the state of charge of the electrochemical batteries which is the controlled quantity. As a case study, it is proposed a simulation of a suitably redesigned hydrogen-fuelled railway train operating, over an existing non-electrified line, for the L’Aquila (Italy) urban transportation service. The main components of the railway line and vehicle powertrain are designed, and the hydrogen consumption for railway operation is estimated.