BRITISH Transport Police made five arrests in drugs operations at Newport and Cardiff railway stations.
Officers, accompanied by sniffer dogs, were at the stations last Thursday and Friday respectively.
Insp Gary Ash said the aim of the operation was in response to concerns raised about drugs and drug-taking at the stations.
During the two-hour operations, four people were fined for possession of cannabis and one was issued with a warning.
Insp Ash added: "I hope this operation acts as a deterrent to those who think it is OK to carry drugs at stations and on trains."
Anyone who sees drug taking or anti-social behaviour on the rail network can call British Transport Police on 0800 40 50 40 or Crimestoppers anonymously on 0800 555 111.