The U.S. Supreme Court case Minneapolis & St. Louis Railroad Company et al. v. Peoria & Pekin Union Railway Company in 1925 revolved around a dispute between two railway companies over the use of tracks and facilities owned by one company but used by both under an agreement dating back to 1881. The Minneapolis & St.Louis Railroad (M&StL) argued that the Peoria & Pekin Union Railway (P&PU) had violated their contract, which allowed M&StL to use certain tracks and facilities for its trains in exchange for payment based on usage rates agreed upon at the time of signing, with any changes subject to mutual consent only. However, when P&PU unilaterally increased these charges without M&StL's approval, it led to this lawsuit where M&StL sought relief from what they considered unjustified increases imposed by P&PURC. The court ruled in favor of M&SRL stating that while contracts could be modified due to changing circumstances or public interest considerations; unilateral alterations were not permissible unless explicitly provided for within the original agreement itself.

In the dissenting opinion for Minneapolis & St. Louis Railroad Company et al. v. Peoria & Pekin Union Railway Company, Justice Holmes disagreed with the majority's decision that a contract between two railway companies was unenforceable due to it being in violation of federal law prohibiting pooling agreements among railroads. He argued that not all contracts involving railways were automatically subject to this federal regulation and believed that the specific agreement in question did not constitute a pooling arrangement as defined by law but rather represented an ordinary business transaction intended to facilitate efficient operation and reduce costs. Furthermore, he contended that even if such an agreement could be interpreted as falling under anti-pooling legislation, it should still be enforceable unless explicitly prohibited by Congress or clearly detrimental to public interest – neither of which conditions he found applicable in this case.