What might suggest inefficiency in speed indicators?

Inaccurate speed readings suggest inefficiency in speed indicators because they can lead to misunderstandings about a train's actual velocity. If the readings displayed by the speed indicator do not reflect the true speed of the train, it could result in increased safety risks and operational issues. For example, if a train is moving faster than what is indicated, it may not comply with safety regulations or speed limits, potentially leading to unsafe situations.

Consistent speed readings with track speed, a speed indicator functioning at a perfect rate, or clear visibility conditions would not typically point to any inefficiency. Instead, they suggest normal operation and correct functioning of the speed monitoring system, contributing to safe and efficient train operations.