The Washington Post reported Thursday that Amtrak would be reducing its schedule and canceling some trips.
The Omicron variant leads to record-high positivity rates, which is why the schedule reductions are due.
There are some overnight trains in the Northeast Corridor and long-distance routes between New York and New Orleans that will be affected. Trips between Boston and Newport News, Virginia, as well as between Washington, DC, and Springfield, Massachusetts, have been canceled.
A representative for Amtrak told the Washington Post that it "regrets any interruption."
The representative said that they were monitoring the conditions and would make any necessary adjustments.
In December, Amtrak warned that it could be forced to reduce service if there weren't enough employees who had been vaccined. The railroad said on December 14 that it would no longer require vaccine for its employees and that it did not expect to have to cut service.
There have been more cases of COVID-19 since then.
Omicron is hurting airlines.
Air travel has also been disrupted due to a surge in cases and busy holiday season. As more employees test positive for COVID-19, airlines have had to cancel flights.
Air traffic control staff case counts can lead to further delays. Over 20,000 flights have been canceled since December 24.
The Omicron variant has spread to much of the country and the US is reporting record-high new daily COVID-19 cases.
Travel delays have been caused by winter weather in the US.