A more thorough explanation:

The Safety Appliance Act is a federal law that governs the safety of equipment used by railroads in interstate commerce. This law is found in the United States Code Annotated (USCA) under sections 20301 et seq.

One example of the Safety Appliance Act in action is the requirement for all railroad cars to have automatic couplers. These couplers allow cars to be connected and disconnected without workers having to climb between them, reducing the risk of injury.

Another example is the requirement for all locomotives to have air brakes. Air brakes allow the train to stop more quickly and safely than manual brakes, reducing the risk of accidents.

These examples illustrate how the Safety Appliance Act aims to improve the safety of railroad workers and passengers by mandating specific safety equipment and practices.