White Pass & Yukon Route No. 104 is a DL-535E type narrow gauge diesel locomotive built by the Montreal Locomotive Works in May 1969 for the White Pass & Yukon Route (WP&Y) in Skagway, AK. It is one of ten DL-535E type diesels that were custom-built for the WP&Y between 1969 and 1971. In 1992, it was sold to Sociedad Colombiana de Transport Ferroviaro in South America alongside sister diesels 101, 103, 106, and 107, but were later sold back to the WP&Y in 1999 for tourist excursion service.
It would serve in excursion service for the WP&Y until early 2020 when the railroad announced that would be replacing their old diesel fleet with brand new E6000CC-DC type locomotives built by National Railway Equipment Company in Mount Vernon, IL. As of today, it currently sits in storage in Skagway, AK alongside sister diesels 108, 109, and 110. Sister diesels 101, 103, 106, and 107 were eventually sold in April 2020 to the Durango & Silverton Narrow Gauge Railroad (D&SNG) in Durango, CO where they still operate in tourist excursion service as of today.