What characterizes an Absolute Signal?

An Absolute Signal is specifically characterized as a block or interlocking signal that does not feature a number plate. This signifies that it governs the movement of trains by restricting access to a portion of track until it is safe to proceed. The absence of a number plate indicates that the signal is not primarily used for distinguishing specific blocks, but rather serves as a definitive indication of whether a train can proceed or must stop.

This is critical for ensuring safe train operations, as it provides clear authority for train movements. In contrast, the other options describe other types of signaling systems or features that do not define an Absolute Signal. For instance, a signal with a number plate distinguishes specific block sections and a colored light signal can represent various statuses but does not inherently convey the same information as an Absolute Signal. A digital signal system may employ various technologies but does not define the traditional characteristics of an Absolute Signal in the GCOR framework.