Block signals that enforce train operation at a predetermined reduced speed are classified as what type of signals?

Block signals that enforce train operation at a predetermined reduced speed are classified as G.T. signals, which stands for "Grade Time" signals. These signals are specifically designed to alert train operators that they must adjust their speed based on the conditions and requirements set on that section of the track. G.T. signals indicate that a controlled decrease in speed is necessary to ensure safety and compliance with operational protocols in that area.

By enforcing a reduced speed, G.T. signals help to mitigate risks associated with various track conditions, such as curvature, grade changes, or other safety concerns. This classification directly relates to the operational guidelines that improve safety for both the train and its passengers. The proper identification and adherence to G.T. signals are crucial for maintaining smooth and safe train operations, especially in scenarios where higher speeds could lead to accidents or derailments.