White Pass & Yukon Route No. 106 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, 104, 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 being sold in April 2020 to the Durango & Silverton Narrow Gauge Railroad (D&SNG) in Durango, CO alongside sister diesels 101, 103, and 107. While 101 and 107 were delivered to the D&SNG in September 2020, 103 and 106 weren't delivered until September 2021.
It was temporarily placed in storage in Durango, CO alongside custom-built MP2000NG type diesels Nos. 1201 and 1202 and eventually entered service on the D&SNG in June 2024 to continue running in tourist excursion service. Like 101, 103, and 107, it was also repainted from its WP&Y yellow and turquoise paint scheme to a D&SNG orange and scarlet paint scheme.