Castlegate is a large cliff-like structure of Cretaceous age sandstone that nearly blocks the lower end of Price River Canyon in Utah. The Union Pacific’s Provo sub follows the Price River downstream from Colton after crossing Soldier Summit. The tracks pass immediately below this thin fin of rock that juts out from the east wall of the canyon forming a narrow slot for the river and railroad to pass through. There used to be a similar, but smaller, twin on the west side, but it was blasted away by the Utah Department of Transportation years ago during construction of US Highway 6. As seen here, UP3973 leads the MROHP-8 train of empty crude oil tanks destined for the yard at Helper and then to be further forwarded to the oil loadouts.
