Union Pacific GE AC4400CW No. 6227 sits in the locomotive shop at South Morrill, Nebraska, on September 15, 2017.

A worker at Union Pacific’s South Morrill Locomotive Facility attaches the old exhaust stack from UP GE AC4400CW No. 6704 to a new prime mover that is being prepared for installation during the ov... (more)

General Electric AC4400CW locomotives are abundant at the locomotive servicing tracks at Union Pacific’s South Morrill yard in Nebraska on the afternoon of September 13, 2017.

Several Union Pacific GE AC4400CWs receive work outside, or await further rebuilding inside, the railroad’s locomotive shop located at South Morrill, Nebraska, on September 15, 2017. In mid-Octobe... (more)

A new prime mover is being moved across the shop floor via overhead crane for installation in Union Pacific GE AC4400CW No. 6704 during an overhaul at UP’s South Morrill Locomotive Facility on Sep... (more)

A bad order traction motor is in the process of being changed out on Union Pacific GE AC4400CW No. 6300 at the railroad’s locomotive shop in South Morrill, Nebraska, on September 14, 2017. Using a... (more)

Union Pacific GE AC4400CW No. 6704 is at the railroad’s South Morrill Locomotive Facility for an overhaul, with the new prime mover arriving from the staging area in the shop on September 14, 2017... (more)

Union Pacific GE AC4400CW No. 6704 gets a scrubbing by Kaleb Ewing and Martin Hernandez following the locomotive’s overhaul at UP’s South Morrill Locomotive Facility in Nebraska on September 15, 2... (more)

Machinist Hector M. Ramirez operates the massive Simmons wheel lathe truing the wheels of Union Pacific GE ES44AC No. 8260 in the railroad’s locomotive shop at South Morrill, Nebraska, on Septembe... (more)

Two Union Pacific GE AC4400CWs have work done in the railroad’s locomotive shop at South Morrill, Nebraska, on September 15, 2017. On Track 2, No. 6227 is having a new water pump installed, while ... (more)

Two Union Pacific electricians work on PTC equipment installation for UP GE AC4400CW No. 6778 in the railroad’s locomotive shop at South Morrill, Nebraska, on September 14, 2017.

A bad order traction motor is changed out on Union Pacific GE AC4400CW No. 6300 at the railroad’s locomotive shop in South Morrill, Nebraska, on September 14, 2017. Alan Ford writes up what is wro... (more)

The 16-cylinder 7FDL16 from Union Pacific GE AC4400CW 6704 sits on the shop floor after removal from the locomotive. It pretty obvious which cylinder or two had a defect or problem as much of it i... (more)

A new prime mover is being prepared for installation in Union Pacific GE AC4400CW No. 6704 during an overhaul at UP’s South Morrill Locomotive Facility on September 14, 2017. The old prime mover i... (more)

Several GE AC4400CWs and AC4400CW-CTEs await repair or overhaul outside Union Pacific’s South Morrill Locomotive Facility on September 15, 2017. This Nebraska shop specializes in working on GE AC4... (more)