What is the maximum allowable speed for making a coupling between cars to prevent damage?

The maximum allowable speed for making a coupling between cars is established to minimize the risk of damage to the equipment as well as to ensure the safety of the crew involved in the coupling process. When considering the option of 4 MPH, this speed has been determined to provide an effective balance between the need for operational efficiency and the need to prevent excessive impact forces that can occur at higher speeds.

At higher speeds, the kinetic energy involved in the coupling process increases, which can lead to equipment damage, unnecessary wear and tear, and safety concerns for personnel. By limiting the speed to 4 MPH, the coupling procedure becomes more controlled, allowing for a smoother and safer engagement between the cars. This practice is an essential aspect of railway operations, ensuring that safety standards are adhered to and operational integrity is maintained.

The other options present speeds that may lead to more significant impacts during the coupling process, increasing the likelihood of damage to both rolling stock and the associated coupling mechanisms. Therefore, the selection of 4 MPH reflects industry best practices aimed at optimizing both safety and operational effectiveness during train operations.