The GP50 is a somewhat rare engine by North American standards, so it’s pretty cool to find a model of it. I suspect the livery was ordered during the drawn out merger of MoPac and UP. Once it was complete, (only took 17 years!) the locomotives could be patched and relettered during regular maintenance.
Because of the time it takes to repaint an engine, it’s often done only during major overhauls. It isn’t unusual to see locomotives wearing colors and insignia of predecessor roads for years, even decades, after mergers and buyouts. Just last week, my daughter and I watched a Canadian National mixed freight pulled by a pair of SD60sSD70s. The lead engine was still in full Illinois Central markings, with only CN identifying marks patched below the cab windows. EDIT- Nope, there actually were NO CN ID marks below the cab windows. Oddly, the second locomotive was also a former IC unit but it had been repainted in the full CN colors.
Because of the time it takes to repaint an engine, it’s often done only during major overhauls. It isn’t unusual to see locomotives wearing colors and insignia of predecessor roads for years, even decades, after mergers and buyouts. Just last week, my daughter and I watched a Canadian National mixed freight pulled by a pair of SD60sSD70s. The lead engine was still in full Illinois Central markings, with only CN identifying marks patched below the cab windows. EDIT- Nope, there actually were NO CN ID marks below the cab windows. Oddly, the second locomotive was also a former IC unit but it had been repainted in the full CN colors.