Union Pacific MDVRO (Denver to Roper Yard) manifest storms out of Tunnel 18 east of Crescent, Colorado, on August 25, 2001. Lead locomotive UP No. 4766 is a former Southern Pacific SD45 that SP rebuilt in 1981 to a “SD40-2” with upgraded Dash 2 electrical componants and a 3000-horsepower 16-cylinder engine.