By the 1970s the Aspen and Altamont Tunnels east of Evanston, Wyoming were again becoming a bottleneck for the Union Pacific, this time because of clearances designed for an earlier era of rolling stock, resulting in cumbersome re-routing of the new HiCube boxcars. Under then-president John C. Kenefick the tunnels were enlarged at a cost of $7 million, a prescient decision considering the flood of double-stack traffic to come in the not-so-distant future. Here a westbound is seen in the background having just emerged from the Altamont Tunnel (out of sight behind the embankment at right), with the line to Aspen Tunnel in the foreground. Note the bi-directional signals, which enable the two tunnels to be operated as part of a bi-directional double-track main.
