ANACORTES — A federal appeals court has upheld a ruling protecting the Swinomish Indian Tribe’s right to sue to enforce an agreement that restricts the number of trains that can cross its reservation in northwest Washington.

The tribe sued BNSF Railway in 2015, alleging the company was violating an agreement that only allowed two 25-car trains to cross its reservation on Fidalgo Island each day. The lawsuit said multiple 100-car trains carrying crude oil cross the reservation each week.

The case will now return to federal district court.