Train companies have been accused of ignoring the needs of cyclists with a ban on taking bicycles on board after the London to Brighton Bike Ride.
Thousands of cyclists take part in the London-to-Brighton ride
Roads into Brighton were gridlocked on Sunday when motorists poured into the city to meet many of the 27,000 cyclists who took part in the ride.
The Cyclists Touring Club said people were stranded because train operators refused to take riders back to London.
Southern Trains said its new fleet could not carry large numbers of bikes.
"The rail operators seem incapable of sorting out the very basic issue of managing the overspill of cyclists from the London to Brighton Bike Ride," said Cyclists Tourist Club (CTC) spokesman Dave Holladay.
"This could easily have been handled by effective management and the help of local volunteers - as happened for almost 20 years."
Until last year, many of the riders in the annual bike ride, organised by the British Heart Foundation (BHF), returned to the capital by rail.
Special services were run with seats removed from old carriages.
But in 2004, following the replacement of the old slam-door trains with sliding door rolling stock, the BHF was told this was no longer possible.
CTC said it had suggested that dedicated cycle-carrying trains could be provided but Southern and Thameslink had shown no interest in the idea.
"Southern no longer has the capacity to carry the large number of cycles, which was possible with the old slam door trains," said a spokesman.
He said the BHF made alternative arrangements for registered riders, including park-and-ride schemes and lorries to take bikes home.
"For those not registered it was imperative that they made their own arrangements for transporting cycles to and from London and Brighton," the spokesman said.
Thameslink, which also runs services into Brighton, said its carriages had very limited cycle capacity so it decided to ban them completely to avoid being inundated.