This is a custom built HO Scale Alaska RR #4321. It started from a Kato HO Scale SD70MAC Alaska RR #4001. To model accurately the ARR #4321 Phase 3 EMD SD70MAC HEP prototype, several Kato factory shell components were replaced or enhanced with appropriate hand-crafted components:

1. detailed Phase 3 Tier 1 Emissions Standards 4 panel flared radiators,
2. detailed Phase 3 Rear Section (under radiator) cabinets, doors, and grills,
3. dynamic brake cabinet air-intake grills,
4. Electrical Generator Cabinet right side extension,
5. HEP cabinet, doors and grills on right and left side
6. Winterization hatch, with see through grill and lift tabs,
7. Alaska RR SD70MAC style ECAFB (Electrical Cabinet Air Filter Box), with stanchions and hand rail.