What shape are the plugs required to be?

The plugs used in train operations must be square in shape to ensure secure and reliable connections between electrical components. The square design allows for a more stable fit and helps prevent accidental disconnection due to vibration or movement, which can be particularly important in the dynamic environment of rail operations. Additionally, this shape is often standardized in the industry, facilitating compatibility and uniformity across different types of equipment and applications. The other shapes—circular, rectangular, and oval—while they may have their own uses in various contexts, do not provide the same advantages of stability and reliability as square plugs in this specific application.