If a flat spot on a wheel develops en route, what is one condition under which the train may continue its journey?

A flat spot on a wheel can impact the train's safety and performance significantly. Continuing a journey with a flat spot is typically contingent upon the size of the flat spot. If the flat spot is less than 2 1/2 inches in length, it is generally considered tolerable for the continued operation of the train. This threshold allows for the wheel's safe navigation on the tracks without compromising the integrity of the train or the safety of its operation.

In contrast, a flat spot longer than this length, such as 3 inches, is too severe and would likely necessitate stopping the train for inspection and potential repairs. The absence of flat spots is ideal and indicates that the wheels are in good condition, thus allowing for a smooth journey. Reporting all wheel flats immediately is a crucial safety protocol, but in this specific scenario, if a minimal flat spot is present and falls within the acceptable length, the train may continue its journey safely while still adhering to regulations.