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The rail line connects Seattle to Portland

Burlington Northern and Union Pacific Railroads use the track for freight

CNN  — 

A 60-mile stretch of a key rail line in southwest Washington was vandalized in several places Monday, causing a series of delays.

Gus Melonas, a spokesman for Burlington Northern Santa Fe Railway, said a railroad crew working in the area first noticed the problem around 11 a.m. They then began checking the line which connects Seattle to Portland and also carries rail traffic to the eastern part of the country. He says the crews found several instances of tampering that stretched across three counties.

Melonas said traffic was stopped for a couple of hours while and service resumed around 1 p.m. with escorts to ensure safety. The railroad has crews working overnight to complete all the repairs on the line and they are working with local authorities to investigate the incident

The track is used by Burlington Northern and Union Pacific Railroads for freight. On an average day, about 40 freight trains and 10 Amtrak passenger trains use the line, Melonas said.