UP was a major initial purchaser of the Dash 8 locomotive
The Dash 8 Series of locomotives was built by GE starting in the 1980's and continues to be in mainline heavy haul service today. There are 2 main models in the -8 lineup including Dash 8-40C, & Dash 8-40CW, there us also a Dash 8-32 model built for Amtrak. The locos boast 4000 hp and can be seen pulling any type of train from long coal drags to high speed intermodal trains.
In N Scale Atlas leads the way when it comes to Dash 8-40 locomotives.