The U.S. Supreme Court case Pennsylvania Railroad System and Allied Lines Federation No. 90, et al. v. Pennsylvania Railroad Company, et al., in 1924 revolved around a dispute between the railroad company and its employees' union over wage reductions and working conditions during a period of economic hardship for the industry post-World War I. The court ruled that while employers have the right to reduce wages due to financial difficulties, they must do so in good faith without discrimination against union members or violating existing agreements with their workers' unions under Railway Labor Act provisions which protect collective bargaining rights for railway employees.

The dissenting opinion in the case of Pennsylvania Railroad System and Allied Lines Federation No. 90, et al. v. Pennsylvania Railroad Company, et al., argued that the majority's decision to uphold a lower court ruling allowing for an injunction against striking railroad workers was incorrect. The dissenters believed that this decision violated the rights of labor unions to engage in collective bargaining and strike action as part of their efforts to secure better working conditions and wages for their members. They also expressed concern about the potential implications of this ruling on future labor disputes, arguing it could set a dangerous precedent by effectively limiting workers' ability to protest unfair treatment or poor working conditions through industrial action.