Two non-electrified railway lines, one in Norway and the other in the USA, are analysed for their potential to be electrified with overhead line equipment, batteries, hydrogen or hydrogen-battery hybrid powertrains. The energy requirements are established with single-train simulations, including the altitude profiles of the lines, air and rolling resistances, and locomotive tractive-effort curves. The composition of the freight trains, in terms of the number of locomotives, battery wagons, hydrogen wagons, etc. is also calculated by the same model. The different technologies are compared by the criteria of equivalent annual costs, benefit–cost ratio, payback period and up-front investment, based on the estimated techno-economic parameters for years 2020, 2030 and 2050. The results indicate the potential of batteries and fuel cells to replace diesel on rail lines with low traffic volumes.

Electrochemical impedance spectroscopy (EIS) is a powerful technique that can be used to detect small changes in electrochemical systems and subsequently identify the source of the change. While promising, analysis is often non-intuitive and time-consuming, where collection times of a single EIS spectrum can reach several minutes. To circumvent the long collection times associated with traditional EIS measurements, a multi-sine EIS technique was proposed in which the simultaneous application of many frequencies can reduce the acquisition time to less than a minute. This shortened acquisition time opens the possibility to use multi-sine EIS as a real-time diagnostic tool for monitoring the state-of-health of commercial fuel cell systems. In this work, a single-cell proton exchange membrane fuel cell (PEMFC) was characterised using multi-sine EIS, by establishing steady-state impedance response under baseline conditions before systematically changing operating conditions and monitoring the dynamic changes of the impedance response. Our initial results demonstrate that full multi-sine EIS spectra, encompassing a frequency range from 50 kHz to 0.5 Hz, can be collected and analysed using simple equivalent circuit models in 50 s. It is shown that this timeframe is sufficiently short to capture the dynamic response of the fuel cell in response to changing operating conditions, thereby validating the use of multi-sine EIS as a diagnostic technique for in-situ monitoring and fault detection during fuel cell operation.