Speed signs with a yellow background and black writing apply to which trains?

Speed signs with a yellow background and black writing are a universal indication that applies to all rail traffic, including freight trains. This color scheme is used to convey important operational information that is crucial for maintaining safety and efficiency on the rail network.

They are set to convey speed limits that must be adhered to by all types of trains operating in that area, not restricted to just passenger services. The presence of these signs ensures that all rail operators, regardless of the type of service they provide—be it passenger, freight, or regional—are given consistent and clear instructions essential for the safe operation of trains.

Other choices would incorrectly limit the scope of application of the speed signs either to specific types of trains like passenger or freight only, which would not align with the regulations in place aiming to ensure comprehensive safety protocols across the entire rail network. This inclusivity is vital, as various types of trains may utilize the same tracks, and maintaining shared operational standards is key to preventing accidents and ensuring smooth transit.