Railway commuters using First Great Western (FGW) trains left more than 12,000 items of property behind in carriages during 2006.
Found items are kept for 13 weeks
FGW said coats and bags, especially those containing shopping are the most common items people forget to take with them followed by umbrellas and glasses.
Station managers say more than 3,000 items have already been handed in during the first part of 2007.
One of the most unusual items left was a light heavyweight title boxing belt.
It was returned to the owner in time for the title fight and presentation.
"A boxing belt is a first for us and the owner was in touch straight away to claim it back in time for the fight between Tony Oakey and Steve Spartacus," said Andrew Gallaugher, FGW's station manager at Bristol Temple Meads.
"The amount of lost property is increasing year on year and 2007 looks like being the worst yet," he added.
"Cycles, pushchairs, wheelchairs and crutches are also commonplace in lost property, which makes you wonder how the owners made it home once they got off the train," said Mr Gallaugher.
Items left behind that are handed in are kept for 13 weeks after which they are sent to auction.