What type of signals are classified as G.T. signals?

G.T. signals, or "grade crossing signals," are specifically designed to enforce operation at a predetermined reduced speed. The purpose of these signals is to ensure safety in areas where train tracks intersect with roadways or potential hazards, allowing for a controlled and measured approach. By informing train operators of the need to slow down, these signals help mitigate the risk of accidents at crossings.

In contrast, signals that authorize train operation at normal speed would indicate that the operator can proceed without restrictions, which is distinct from the purpose of G.T. signals. Track switching signals focus on directing trains safely between different tracks; however, they do not serve the same safety function in terms of speed regulation. Finally, signals that warn of upcoming hazards provide important information but do not specifically dictate operating speed in the same manner as G.T. signals. Thus, the defining characteristic of G.T. signals is their function in enforcing reduced speed in the interest of safety at critical junctures.