New research from the Rail Safety and Standards Board (RSSB) could allow more people with colour vision deficiency (colour blindness) to work in safety-critical railway roles, such as train driving.
Currently, the Ishihara test is commonly used to check for colour vision deficiency. While it identifies colour-deficient vision, it doesn’t measure the degree of colour vision loss. This means individuals with minor colour vision loss might fail the test, even if they can safely perform the role.
ASLEF, the train drivers’ union, raised concerns that some drivers were being removed from duty unnecessarily after failing the Ishihara test due to minor colour vision deficiencies. This prompted the RSSB to investigate colour vision testing.
The RSSB’s research has led to a proposed two-step approach. The Ishihara test will remain the initial screening, requiring 100% correct answers to pass. Those who fail will then undergo a more detailed Colour Assessment and Diagnosis test to determine the specific degree of their colour vision deficiency. Analysis suggests this new method could deem approximately 47% of those currently failing the Ishihara test as safe to work in these roles.
Luisa Moisio, RSSB’s Director of Research said: ‘For years, people with minor colour blindness have not been able to work in safety-critical jobs on the railway. This could be discriminatory, breaching equality law, by preventing capable people from being considered for employment.
‘Our research has identified a more thorough testing process to establish if someone with colour blindness can safely perform a role. We are now changing medical standards to implement this new fairer testing system, giving more people an opportunity to join the railway family.’
Mick Whelan, general secretary of ASLEF, said: ‘We’re extremely pleased with the successful outcome of the work of the RSSB, which we initiated and subsequently worked with the RSSB to deliver. This will give a greater opportunity for those currently excluded from driving trains to achieve their ambitions.’
The research findings have informed changes to rail industry standard RIS-3789-TOM, which will be published in March 2025.
