About 150 train passengers were told to leave an overcrowded train because of safety concerns.
British Transport Police helped Great Western Railway (GWR) staff with some passengers on the London Paddington to Penzance service who refused to leave at Plymouth.
GWR provided another train to Penzance later on Good Friday and said the service had been busier than usual.
It said it was looking at ways to prevent a similar situation on Monday.
A spokesman from GWR said the 10:00 GMT service was "very busy" when it left London Paddington and it "picked up more passengers" as it travelled towards Penzance.
"Two services arrived at Plymouth ahead of the London Paddington service and terminated there, which resulted in a lot of people waiting to board this train.
"The train manager said the situation was unsafe and asked people standing right by the doors to leave."
He said police assisted staff as some passengers did not want to leave.
GWR said a further six carriages were added to a two carriage train that departed about one hour later and took passengers into Cornwall.