What is meant by "track gauge"?

Track gauge refers specifically to the distance measured between the inner faces of the two rails on a railway track. This measurement is critical because it influences the stability and safety of train operations as well as the compatibility of rolling stock. Different countries and railway systems may use various gauges, which can affect the interoperability of trains from different regions. A wider gauge generally provides more stability, while a narrower gauge can allow for more flexibility in terms of construction and track laying in constrained environments. Understanding track gauge is essential for locomotive engineering, as it plays a vital role in the design and operation of rail systems.