Seven people were fined for cannabis possession after random checks at a Lancashire railway station.
A sniffer dog was used to check commuters using Lancaster station yesterday and Tuesday.
Sgt David Grant, from British Transport Police, said four people were given £80 fixed penalty tickets yesterday after being found with a small amount of the drug.
Three people were given the same punishment the day before.
He said: “It’s one of the things we do from time to time.
“It is unannounced and it’s all designed to make the railway a safer environment for the travelling public and the staff who work here.”