Beech Hurst Park Miniature Railway in Haywards Heath welcomed its 1.5 millionth passengers on Saturday.
The railway, which operates scale live steam and battery electric locomotives, is located within Beech Hurst Gardens.
The lucky passengers were Mr and Mrs Tennant of North Chailey who were visiting the railway with their two young children.
Commenting on the achievement, long-standing Sussex Miniature Locomotive Society (SMLS) member Chris Saunders, who counted down the last 100 passengers, said: “This marks a very significant part of the club’s history and shows how popular the railway is within the local community.
“To put the 1,500,000 figure into context it is nearly equal to the current population of Sussex riding on our railway.”
SMLS welcomes new members aged 12 and above to help run the railway and maintain the facilities.
It is open for rides every Saturday and Sunday between 2pm and 5pm and the 2018 season draws to a close on Sunday, September 30.