Which statement best describes a Standard coupler's feature?

The statement that a Standard coupler is primarily used for freight trains accurately reflects its design and application within the railroad industry. Standard couplers, which include designs like the Janney coupler, are engineered to handle the heavy loads associated with freight transportation. Their robust construction allows them to withstand the stress and forces encountered while moving goods over long distances.

The use of Standard couplers in freight trains enhances safety and efficiency. These couplers can accommodate the different car types utilized in freight operations and provide a strong connection that can effectively transfer pulling forces between cars, vital for maintaining the integrity of the freight train during transit.

Choosing this response highlights the practical function of Standard couplers in the freight sector, ensuring they are suitable for the types of loads and the operational needs of freight service.