Abstract: A retrofit handrail extension system or kit enables a large mining truck to be retrofitted in the field. The handrail extension system includes a first handrail extension member for connecting a first upper portion of a first ladder to a railing mounted to a catwalk around the cabin of the truck and a second handrail extension member for connecting a second upper portion of the first ladder to a forward-facing handrail mounted to an outer surface of the cabin of the truck. The system may include a third handrail extension member for connecting a first upper portion of a second ladder to a first platform railing mounted to a platform beside the cabin of the truck and a fourth handrail extension member for connecting a second upper portion of the second ladder to a second platform railing mounted to the platform beside the cabin of the truck.