HO G2 SD90MAC-H Phase I Union Pacific #8503 (ATHG27220)

HO Scale G2 SD90MAC-H Phase I Union Pacific No. 8503 locomotive is a detailed HO-scale model designed for model railroad layouts. It reproduces Union Pacific's Phase I SD90MAC-H in UP livery, giving hobbyists an authentic late‑1990s UP powerhouse to pull freight on an HO layout.

Union Pacific was the sole buyer of the SD90MAC-H, known to UP as the SD90AC. The first seven units were pre‑production and wore multiple numbers during their lifetimes. The 8500 series—including No. 8503—consists of the second and third orders delivered between 1997 and 1999 before the renumbering to the 8900 series. In this Phase I batch, some numbers—8509, 8512, and 8520—were modeled with the starter capacitor removed and the EOT mounted further forward on the fuel tank, adding extra realism for prototypical 1990s UP operation.