Built in 1916 by blasting through solid granite rock, the twin tunnels were lined with timber to protect trains from falling pieces of granite, which is easily cracked by temperature extremes of freezing and thawing. The remains of this lining can still be seen today. A wooden snowshed was also built between the concrete arch and the twin tunnel portal to protect the portion of track not covered. The twin tunnels have a combined covered length of 2,057 feet. Today, the remains of the rotting timber lining and falling rocks make the tunnel extremely dangerous.