From the main yard in Salt Lake City, to the yard in Ogden, Utah, this route would give access to a variety of freight services, such as shunting in either the Ogden or Salt Lake City yards, or taking a variety of freight services between the yards. In addition, the UTA FrontRunner runs along this segment of tracks, with nicely spaced stops and a top speed of 79 MPH, that allows you to get up to a nice speed along the entire route. This particular route would be open to a future expansion down south to Provo, where there is another, smaller yard, as well as the actual terminus for the FrontRunner, which is the only commuter rail route in Utah.
Rio Grande locos such as the GP60, SD50, SD40T-2, SD7/9, GP7/9, and GP30 would be great to see on this route if it was set in the 1970s-80s. The Utah RR MK5000C/MK50-3s and some UP diesels (maybe a GP60, SD70M, ES44AC, or ET44AC) would be great for a modern version of the route. SP locos such as the GP60, SD45, SD45T-2, SD40T-2, SD70M, C44-9W, and AC4400CW would be great to see in a late 1980s-1990s version of the route.