Stop and examine
The Stop and Examine rule was a United Kingdom Rulebook rule on the former British Railways. It required train crews to stop a train and investigate the cause if they became aware of any unusual conditions that might endanger the train. The Stop and Examine rule was made defunct after railway privatisation, when the modular format rulebook was introduced. Rules are no longer given names, but instead are referred to by their location in the rulebook. In this instance it is Module TW1 (Preparation and movement of trains)—which states: