Swindon railway station has become a "gateway" for young people bringing class A drugs into the south west from London, police say. British Transport Police says good public transport links to the capital means criminals are sending children to ferry drugs via the town.
The pandemic has made it easier to spot people transporting drugs due to low passengers numbers, the force added.
The Children's Society says the children need to be seen as "victims".
The head of a dedicated British Transport Police (BTP) drugs taskforce, Det Supt Gareth Williams, said: "Swindon is a bit of a gateway location for going deeper into the south west, but also a great train route from London. What we've seen is mainly London residents being involved in the local (Swindon) drug market and on into Wiltshire. With dwindling passenger numbers that are involved, people who are involved in (drug dealing) stand out."
A key aim of the taskforce is to identify and safeguard vulnerable children being used to transport drugs and cash. The BTP has partnered with The Children's Society on its Look Closer awareness campaign, which encourages people to look out for children being groomed and exploited while on the rail network. The charity's James Simmonds-Read said it was "really important" that police capture the "real criminals, who are the people controlling these children".
"We've been seeing some huge strides to recognise these children as victims and to make sure they get the support they need and to go after the perpetrators," he said.
But he said across the country it was still the case that many children were "treated as criminals."
Det Insp Paul Franklin, from Wiltshire Police, said it is working with neighbouring forces to reduce the impact of drug gangs. Three men from London were jailed in November for offences committed in Swindon as part of a joint investigation between the force and the Metropolitan Police. Shaun Brown, 23, was jailed for five years for two counts of conspiracy to supply class A drugs, while Anthony Brown, 29, was jailed for 34 months over one count of conspiring to supply class A drugs and another of conspiring to supply class B drugs.
Alexter Tonto, 19, was detained in a young offender institution for two counts of conspiring to supply class A drugs.
"This work doesn't stop," Det Insp Franklin said. "We know what harm these networks cause within our communities and we will strive to ensure that those members of County Lines gangs who commit offences in Wiltshire are identified, arrested and the full force of the justice system applied."