A train coupler is a crucial mechanical device located at both ends of a railway vehicle, designed to connect rolling stock together to form a train. Its primary functions are to link cars and locomotives, transmit draft and buffing forces between them, and often incorporate an integrated system to automatically connect air brake lines. Modern railways predominantly use automatic couplers, such as the Janney or SA3 types, which engage upon impact without the need for manual intervention by workers between the cars. This key component must possess exceptional strength, durability, and reliability to withstand immense tensile and compressive forces during operation, ensuring the safe and efficient movement of trains.