Regulators say railroads must examine how they build trains

Federal regulators say railroads need to re-examine how they assemble their trains. The call comes after string of derailments in recent years that were partly caused by the way empty and loaded cars were mixed together with locomotives. Heavy cars at the back of a train can push and pull against empty cars in the middle of a train as it goes over hills and around corners. Those forces have become more of a problem as the industry increasingly relies on longer trains with a mix of all kinds of freight aboard. The Federal Railroad Administration cited six derailments since 2021 where those forces were a factor.