Father Christmas will be handing out free presents to local children on board two First Capital Connect Thameslink route train services this Saturday.
Face painters and balloon artists will join Santa on the 10.24am Bedford to Brighton service and 1.04pm Brighton to Bedford return journey – both regular timetabled trains.
"Every year we like to create a Santa Special for children and their parents or carers along the route," said Keith Jipps, First Capital Connect's customer service director.
"It's one of the ways we can say thank you to our passengers."
First Capital Connect is working with the Rotary Club of St Albans Verulamium whose members will be on board collecting for charity throughout the journey.
The eight-carriage train is a scheduled service and will leave Bedford at 10.24am. Passengers will pay the normal fare.