Crews continued to remove earth and debris from Tunnel 13 after a fire was started last month inside the Siskiyou Mountain passage. Burning creosote-coated wooden supports, the fire caused the collapse of a 300-to-400-foot section of the tunnel, officials said. Investigators said they believe transients or trespassers sparked the Nov. 17 blaze.

Crews didn’t declare the fire officially out until Monday because portions would start to smolder as air flowed through the tunnel, said Mark Wohlers, administrative affairs manager for the Central Oregon and Pacific Railroad Co. The railroad company planned to remove the burned timbers, replacing them with steel joists. Sections of railroad track also must be repaired because they buckled and expanded during the fire, officials said.

An average of two freight trains, mainly carrying timber products, used the tunnel each day before the fire, Wohlers said. Until the railroad reopens the tunnel — near the summit of Interstate 5 just north of the California state line — trains are being routed through Eugene and Weed, he said.

Tunnel 13 made history on Oct. 11, 1923, when 23-year-old twins Ray and Roy D’Autremont and their teenage brother Hugh attempted to rob a Southern Pacific Railroad train near the tunnel’s south entrance. The brothers killed four people but left empty-handed. They were caught in 1927 following a worldwide manhunt.