Which of the following is considered part of a switch in the railway track?

A switch, commonly referred to as a turnout, allows trains to move from one track to another on a railway line. It consists of several critical components, with the wing rail being one of the key elements.

The wing rail is situated at the outer side of the switch, adjacent to the main track. Its primary function is to guide the wheel flanges as a train transitions from the main track onto a diverging track. This helps ensure a smooth and stable change in direction for the train. By providing support and alignment, the wing rail reduces the risk of derailment and enhances overall safety during track switching.

In contrast, the other options are components related to track construction or other functionalities, but they do not specifically pertain to the switch mechanism. For instance, lead rails are typically found in the approach to switches, splice rails are used to join sections of track together, and high blocks are signaling components used to indicate track conditions. However, they do not serve the same role as the wing rail in the context of a switch's operational design.