  In complex networks, centrality metrics quantify the connectivity of nodes
and identify the most important ones in the transmission of signals. In many
real world networks, especially in transportation systems, links are dynamic,
i.e. their presence depends on time, and travelling between two nodes requires
a non-vanishing time. Additionally, many networks are structured on several
layers, representing, e.g., different transportation modes or service
providers. Temporal generalisations of centrality metrics based on
walk-counting, like Katz centrality, exist, however they do not account for
non-zero link travel times and for the multiplex structure. We propose a
generalisation of Katz centrality, termed Trip Centrality, counting only the
paths that can be travelled according to the network temporal structure, i.e.
"trips", while also differentiating the contributions of inter- and intra-layer
walks to centrality. We show an application to the US air transport system,
specifically computing airports' centrality losses due to delays in the flight
network.
