Amtrak began requiring customers to cover their faces in stations, on trains and thruway buses Monday.

The new policy, which was announced last week, states that facial coverings can be removed when customers are eating in designated areas, in their private rooms, or seated alone or with a travel companion in their own pair of seats. Small children who are not able to maintain a facial covering are exempt from the requirement.

Amtrak, which carried more than 12 million passengers on its Boston-to-Washington, D.C., trains in the most recent fiscal year, already has limited bookings to 50 percent of capacity and restricted some seating areas in rail cars. Going forward, it will offer enhanced services on its mobile apps to reduce contact points; one would allow passengers to pre-order food to pick up on board, which would reduce waiting time in the dining car. It is also only accepting cashless payments in stations and on trains for the time being.

In a statement issued by the company, Amtrak President and CEO Bill Flynn said, "The safety of Amtrak’s customers and employees is our top priority and requiring a facial covering is one more way we can protect everyone."

Amtrak continues to operate as an essential service for those who still have to travel. "Our services will be even more critical as our nation recovers,” Flynn said.

The three biggest U.S. airlines - American Airlines, Delta Air Lines and United Airlines -- previously announced that they would require passengers to wear face masks during flights.

Face coverings remain optional on other airlines.

Democrats in Congress have been pressuring the Trump administration to require masks, which they say will help protect passengers and airline crews from the virus that causes COVID-19.

Beyond masks, several airlines are blocking at least some middle seats, but they say that's just a temporary measure. Airlines say they are stepping up airplane cleaning and taking other steps during the virus pandemic.