Summary: The "Tap Line Case" was a Supreme Court case that answered the question of whether a sawmill that operates its own private railroad should be allowed a division of rates on their outgoing lumber. The court looked at the specifics of over 100 companies, in each case deciding if the chartered railroad demonstrated the movement of passengers and freight beyond the mere shuttling of employees and wood products of the parent company. The published decision included over 100 descriptive summaries of individual railroads in Texas, Louisiana, Arkansas and Mississippi.

Part 1, Decided April 23, 1912
1. Introduction and summary of opinions.
2. Discriminations resulting from allowances.
3. What is a tap line? Tap lines generally described.
4. General principle controlling the controversy.
5. Each case must stand on its own facts.
6. The log movement to the mill.
7. Use of passes by tap-line officers.
8. The individual cases described.
9. Cases.
10. Supplemental report.

Part 2, Decided May 14, 1912
1. Supplemental Report of the Commission.
2. Cases.
3. Irregular practices of tap lines.