Vandals sparked chaos for hundreds of rail passengers by throwing a pushchair and a bicycle on to train tracks in Kent.
More than 20 trains were delayed and four were cancelled while the objects were removed from the line in Gravesend on Sunday night.
The total delay to trains was more than 1,100 minutes - or just over 18 hours - with both objects believed to have been thrown from Stanbrook Road footbridge, Network Rail said.
At 9.43pm the 8.20pm Ramsgate to St Pancras International train struck an empty pushchair, and around 45 minutes later the delayed 9.29pm service from Faversham to St Pancras International hit a bike.
The power had to be turned off while the bike was removed from under the train, which reached its destination 157 minutes late.
"Both incidents could have been much more serious, and it's sheer luck that nobody was hurt," said Network Rail South East route crime manager Alice Morton.
"I would appeal to anyone who thinks this sort of stunt is funny to think again."
Anyone with information should contact British Transport Police by texting 61016 or calling 0800 405040 quoting reference 459 05/06/2016 or Crimestoppers on 0800 555111.
