Some 1.7 billion train journeys were made in Britain during the past year, according to industry data.
This represents a 3.7% rise on the previous 12 months, the Rail Delivery Group (RDG) said.
The figures were boosted by growth in London and south-east England, where the number of journeys increased by 4.2% to 1.2 billion.
Long distance routes grew by 3.3% to 139 million, with regional journeys up 2.3% to 379 million.
The RDG calculated the figures using data from the rail industry's central ticketing system for the period from April 1 2015 to March 31 2016.
It said revenue from passengers grew by more than 5% to £9.3 billion in 2015/16 due to the increase in journeys, with an average of 97p in every pound being invested in running and maintaining the railway.
The organisation's chief executive, Paul Plummer, told the Press Association: "Rail keeps Britain moving, but our network is very busy at times due to a big increase in services as passenger numbers have doubled.
"It is vital that we invest and plan long-term for this ever-growing demand."
But Mick Cash, general secretary of the Rail, Maritime and Transport union, said rail staff are "sick and tired" of train companies trying to take credit for the "daily miracle" of transporting people around the network.
He went on: "Their profiteering is a hindrance to expanding and improving services.
"We may well be moving more passengers but for many it's at an eye-watering price to travel on rammed out and overcrowded services while the train ?bosses are laughing all the way to the bank."