Beyond power source, differentiate the primary operational and structural design considerations that lead to distinct locomotive classifications for heavy haul freight versus high-speed passenger service, referencing specific wheel arrangements (e.g., Co-Co vs. Bo-Bo).

Locomotives designed for heavy-haul freight service and high-speed passenger service exhibit distinct operational and structural design considerations driven by their primary functions: moving immense weight at moderate speeds versus transporting people rapidly and comfortably. Beyond the power source, these differences manifest significantly in tractive effort requirements, braking systems, adhesion management, locomotive weight distribution, bogie and wheel arrangements, and carbody structures. Heavy-haul freight locomotives prioritize high tractive effort, which is the pulling force exerted by the locomotive, especially at low speeds to start and accelerate very long and heavy trains. This necessitates a design that maximizes adhesion, the grip between the locomotive's wheels and the rail. To achieve this, these locomotives are typically very heavy, increasing the downward force on the rails. Their robust dynamic braking systems, which use the traction motors as generators to dissipate kinetic energy, are crucial for controlling the immense mass of freight trains, often supplemented ....