EVERETT — Nearly all trains serving Amtrak Cascades temporarily suspended service after the passenger rail agency discovered corrosion problems in passenger train cars widely used on the route.

Amtrak found corrosion issues in several Horizon rail cars, it announced Wednesday, which the rail agency uses for nearly all of its trains on the Amtrak Cascades route. The agency “decided to remove the equipment from service after learning of additional areas of concern from intensive inspections of multiple cars,” the announcement read.

In the meantime, buses will provide service at the same Amtrak stations where the trains stop. Bicycle reservations will still be honored on the buses, and riders who purchased business class tickets will be downgraded to coach class. They will receive a refund for the price difference.

Amtrak Cascades provides daily rail service between Eugene, Oregon and Vancouver, British Columbia in Canada. There are stops in Everett, Edmonds and Stanwood. It is partially funded by the Oregon and Washington departments of transportation.

The suspension took 70 Horizon rail cars across the country out of service, 26 of which are on the Amtrak Cascades route. Amtrak’s next-generation train sets, known as “Airo,” are set to arrive on the Amtrak Cascades route by 2026.

One daily round trip, between Eugene and Seattle, will still be served with train service. All other routes will be replaced with bus service through at least Sunday, an Amtrak spokesperson said Wednesday. The agency will redistribute other trains from its national fleet to replace the grounded trains.

Bus service will continue beyond that date if a plan is not yet ready to replace the train sets which have been pulled from service, said Janet Matkin, a spokesperson for the Washington State Department of Transportation.

“A shutdown like this has not happened previously on Amtrak Cascades,” Matkin said.

Will Geschke: 425-339-3443; william.geschke@heraldnet.com; X: @willgeschke.