Amtrak ridership

As Amtrak ridership has fluctuated with the predictability of a train schedule that no one trusts, global cruise ship passengers have moved in almost perfect synchrony, producing a correlation that suggests either that the same people who ride trains also ride cruise ships or that the travel industry breathes with a single set of lungs. The coefficient is 0.946 across eight years, during which both metrics rose, collapsed in 2020, and recovered with the jerky optimism of industries that have survived a near-death experience and would prefer not to discuss it.

Amtrak ridership grew from about 30 million in 2015 to 32 million by 2019, cratered to 12 million in 2020, and began recovering toward 28 million by 2022. Global cruise passengers followed an almost identical pattern: growing from about 23 million to 30 million, dropping to near zero in 2020 as ships became floating petri dishes of international news coverage, and recovering to about 26 million by 2022. The pandemic is the obvious shared variable—both industries transport large numbers of people in enclosed spaces, both were devastated by the same public health crisis, and both recovered as travel restrictions lifted. The pre-pandemic correlation is also strong, as both track general travel demand driven by disposable income and consumer confidence.

Eight years of trains and cruise ships moving together is a story about the travel industry as a unified organism: when people travel, they travel by all means, and when they stop, they stop completely. The pandemic compressed a century's worth of disruption into two years, and both industries felt it identically. The train pulled out of the station, the ship left the port, and 2020 cancelled both tickets.