Lagerlunda Rail Accident

A Swedish rail accident in 1875 caused by unclear signaling between a station master and a steam engine driver, which caused a head-on collision killing 9 people. An investigation by ophthalmologist Frithiof Holmgren (who the previous year had invented Holmgren’s Wool) suggested that the driver’s Colorblindness could have contributed to the accident. This finding prompted the introduction of mandatory color-vision screening of railroad personnel. However, more recent analyses dispute color blindness as the main cause of the accident.