What is a Tunnel Bolster?

A Tunnel Bolster is specifically referred to as a crossmember that supports the gooseneck tunnel in container chassis. The gooseneck tunnel is an integral part of the chassis design that helps in accommodating the trailer's neck, allowing it to provide smoother transport while maintaining the container's stability. This structural component plays a crucial role in distributing the load effectively and ensuring safety during operation. It is important in container transport, especially for intermodal shipping, where the connection between the container and the transport vehicle must be secure and able to handle heavy loads.

The other options do not accurately represent the definition of a Tunnel Bolster and focus on different aspects of container and transport engineering. While a structural member in railways and container flooring are relevant to the larger context of container transport, they do not pertain specifically to the function and definition of a Tunnel Bolster. A device for exchanging air in containers also falls outside the scope, as it relates more to ventilation systems rather than structural support.