Final answer:
A resume speed signal is a fixed signal located at a point where a train of vehicles had previously stopped or slowed down but then increased speed again.
Step-by-step explanation:
A resume speed signal is typically found on railway lines. It is a fixed signal located at a point where a train of vehicles had previously stopped or slowed down but then increased speed again. This signal is used to indicate to the train operator that they can resume their previous speed.