Heavy haul freight railroads carrying bulk materials such as coal or iron ore are characterized by several unique challenges relating to investment in construction and maintenance as well as achievement of optimal operating efficiency. This paper examines heavy haul railroads around the world in a comparative context that highlights differences relative to operating parameters, degree of integration with upstream and downstream nodes in the supply chain and regulatory regimes. Emphasis is placed on analysis of the extent and impact of mandated access on heavy haul railroads. The authors find that successful heavy haul railroading requires an intense focus on asset productivity and effective coordination of the supply chain. This leads to a bias for bundled above and below rail operations as well as integration with mine and port operators; where this is not possible, multiple railroad operators must have well-aligned incentives. On the other hand, mandated access appears to yield few benefits beyond lower rates, which are primarily a wealth transfer rather than a social welfare gain. In addition, the costs of coordinating access are material, leading to a neutral result at best, or more likely a loss of social welfare. This suggests that regulation of heavy haul railroads should incentivize coordination and integration, and that mandated access to generate competition does not produce an increase in social welfare.