What is the term for a train that is traveling faster than its designated speed limit?

The term "speeding" accurately describes a train that is traveling faster than its designated speed limit. In the context of rail operations, the concept of speeding is crucial as it relates to safety regulations, operational protocols, and maintaining the timetable.

When a train exceeds its speed limit, it increases the risk of accidents and can compromise the safety of both the train and its passengers. Rail authorities enforce speed limits to ensure that trains travel at safe and manageable speeds, particularly in areas that may require special consideration, such as curves or work zones.

The other terms, while related to the concept of speed, do not specifically convey the idea of surpassing a set limit in the same way that "speeding" does. "Overspeeding" might imply exceeding safe operational speeds but is less commonly used in official terminology. "Exceeding" is too broad and does not specifically reference speed limits, while "accelerating" refers to increasing speed in any context without necessarily implying that a limit has been breached.