Girls as young as seven have an "unconscious bias" against engineering, according to research carried out for Network Rail.
The revelation has prompted the company to launch a drive to attract women to the profession including encouraging thousands of schoolgirls to consider a career on the railways through a work-experience scheme and open evenings.
The ‘Switch On, Switch Off’ study, undertaken by InnovationBubble, revealed a "watershed" age of 11 to attract girls into engineering and found that by the age of 14, many girls have fully switched off from engineering as a career.
Network Rail chief engineer Jane Simpson, who joined the engineering industry as an apprentice aged 16 and is now the company's most senior engineer, said role models are vital to fight this kind of conditioning.
"If my school careers adviser had her way, I would have become a nursery nurse or teacher but I wasn't willing to accept being pigeon-holed like that," she said.
“Role models are crucial to show girls and women what’s possible and where their potential can take them. I was lucky to have a female role model who saw my potential and helped me realise it.
"Some quite senior men were astonished that I could talk confidently about complex engineering problems, but they soon came to see me for what I could do, not my gender. As the most senior engineer in one of Britain’s biggest engineering companies I know I can help girls along a similar path and be part of something special.”
To help counter the problem, Network Rail has committed to providing careers advice on working on the railways to some 3,000 teenage girls at five schools in Milton Keynes, the home of Network Rail’s national centre by 2018.
It will also roll-out a work experience scheme supported by Barclays in the new school year and run a series of open evenings at training centres targeted at women, showcasing roles, introducing applicants to staff and building confidence to apply for engineering roles.
Loraine Martins, director of diversity and inclusion at NR, said: "We have some fantastically smart and creative women working for us, making a big difference to the millions of people who travel by train every single day.
"We want even more women to be inspired by the job Network Rail does and to join us as we build a better railway for Britain. We know that a more diverse workforce helps increase productivity and creativity and will help us deliver on our multi-billion pound railway upgrade plan over the coming years."
Transport Minister Claire Perry said: "This government's investment in world-class infrastructure will create jobs and opportunities across the country, but we need to make use of all available talent to ensure Britain stays on the right track.
"Women currently make up a tiny proportion of our surveyors, engineers and construction professionals. We're doing our part asking Crossrail Chief Executive Terry Morgan to lead a transport and infrastructure skills strategy aimed at addressing issues like this, but it's vital that industry leads the way in showing our young people what an exciting career they could have.
"I'm delighted to see Network Rail's efforts to reach out to girls and young women and I'm sure this campaign will have a real impact in making our workforce even more diverse and successful."
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