The Tap Line Cases, decided by the U.S. Supreme Court in 1913, involved a dispute between the United States and Interstate Commerce Commission (ICC) against Louisiana & Pacific Railway Co., among other railway companies. The case centered on whether short-line railroads owned by logging companies could legally receive a portion of long-haul rates under the Hepburn Act of 1906 which prohibited railroads from giving rebates to favored shippers. These "tap lines," as they were called, transported timber from forests to mainline railways for further shipment. The ICC argued that these tap lines were not true railroads but rather instruments of their parent lumber companies used to secure illegal rate divisions or rebates. However, the Supreme Court ruled in favor of the tap line owners stating that they are entitled to compensation for services rendered even if those services only constitute part of a longer haul carried out primarily by another railroad company.

In the dissenting opinion for The Tap Line Cases, it was argued that the majority's decision failed to consider the unique circumstances and economic realities of short line railroads. These smaller railway companies, often referred to as "tap lines," were typically built by lumber companies in remote areas where larger railways did not operate. They served a crucial role in transporting raw materials from these isolated locations to mainline railroads. The dissenting justices believed that charging fees for this service should not be considered discriminatory or anti-competitive since they provided an essential link between resource-rich regions and broader markets. Furthermore, they contended that tap lines could not survive without such compensation due to their high operating costs relative to revenue potential. Therefore, prohibiting them from collecting these charges would effectively eliminate them as viable businesses - an outcome contrary to public interest given their critical function within the national transportation network.