A contributory cause was the failure of anyone to examine the tablet they received by removing it from its pouch and checking that it was the correct one. Although inspection of the tablet was required in the working rules, it was clearly taken for granted that the tablet was correct, since the system had worked faultlessly for years. Indeed, for anyone to ostentatiously examine a tablet may have been a breach of etiquette, as it would imply that the person handing it over might not be competent or trustworthy. Driver Pritchard Jones and Fireman Owen of the express train were conscientious in inspecting every tablet they received; the crew of the stopping train were not.