Washington, DC CNN  — 

Amtrak service will likely be reduced next year as it complies with the upcoming vaccine requirement for federal workers.

Amtrak president Stephen Gardner testified before a House of Representatives committee Thursday that the passenger rail operator does not anticipate having enough employees to run all trains when the mandate takes effect January 4.

He said that 94% of its employees are fully vaccinated and 96% have received at least one dose, which is similar to the vaccination rates of other federal workers. Many engineers, conductors and employees retired or left Amtrak during the pandemic, he said. Amtrak is currently recruiting and hiring today, but it had halted hiring due to funding uncertainty and social distancing requirements that hampered its training.

“This will likely necessitate temporary frequency reductions, primarily for our long-distance services,” Gardner said of the worker shortage.

Gardner said the impact would be felt mostly on long-distance services because of the small crews at stops along these multi-day routes.

“At some of these crew bases across our network, we have a relatively high percentage of unvaccinated employees,” Gardner said.

Amtrak expects to share by next week what services are being reduced. Amtrak plans to return all routes to regular service levels as soon as it has sufficient employees.

Gardner said the pandemic has had a silver lining. In recent months, 30% of passengers were making their first trip on Amtrak, which he said was double the norm before Covid. Amtrak ridership has averaged about 65%-70% of pre-pandemic levels before Thanksgiving of this year. At the Thanksgiving holiday, ridership was 78% of what it was before the pandemic, Gardner said.