c) Attention: This allows a train to proceed past the signal, being prepared to slow down to an appropriate speed for the next signal. It means that the next signal may be at Caution, or may guard a divergence which requires reduced speed (in which case a stop signal at the divergence will indicate the route for which points are set).
d) Proceed: This allows the train to proceed past the signal without slowing down or stopping.
A stop signal invariably has a danger aspect which is usually red (Danger indication) in colour.
Stop Signals are of the following types:
This is the first stop signal on approach to a station. The signal guards entry to the station.