The high number of people working part-time should lead to more flexibility in train ticket charges, according to a campaign group.
The Government and train companies should take urgent action on ticketing and fares, said the Campaign for Better Transport (CBT).
It said many part-time workers were unable to use the train to access jobs because of "inflexible ticketing designed around full-time workers".
CBT public transport campaigner Martin Abrams said: "Our working patterns are changing, but you wouldn't know it if you catch the train to work.
"Many part-time workers in Britain have no alternative but to pay over the odds for a full-time season ticket they don't need.
"Others have been priced off the railways altogether. We urgently need affordable tickets to meet the needs of our growing army of part-time workers."
He went on: "Other countries are miles ahead of us on this. They've introduced part-time railcards and flexible tickets to make it easy and affordable for everyone to get to work.
"As nearly three-quarters of part-time workers are women, this isn't just an economic issue, but a gender equality one.
A spokesman for rail industry body the Rail Delivery Group said: "Britain's railway has been transformed over the past 20 years and we now have the fastest-growing railway in Europe with near-record levels of passenger satisfaction.
"The industry is always looking to improve services and attract passengers and is exploring ways for people to buy tickets that reflect changing lifestyles and make the most of new technology."