DNA swabbing is cracking down on spitting on Scotland's trains, British Transport Police have said.
A sample can be taken to pass on to police
The DNA swab kits were given to ScotRail staff throughout the country a year ago.
If staff are spat at by abusive passengers a sample can be collected, increasing the chance of catching the offender.
So far 36 swabs have been submitted for comparison with the DNA database helping to bring about prosecutions.
The DNA swab kits were introduced in April 2003 and are now available at dozens of stations and more than 230 trains throughout Scotland.
One train driver, who does not want to be named, used the kit after being spat at while trying to protect a conductor from an angry passenger.
He said: "He just spat and if I hadn't got the window closed in time my face would have just been covered in spit.
"We actually used the swab kits that we have on the train and obtained a specimen for the British Transport Police."
The attacker was fined following a successful prosecution and the police say more and more prosecutions are now possible, with one recent case resulting in a four month prison sentence.
Samples are submitted to a forensic scientist to be checked against profiles held on the police's DNA database.
Angela McCulloch is a ScotRail conductor working out of Glasgow Queen Street.
She said: "I think they're a very good idea, it gives a little bit of confidence that if anything like that does happen to us we do have some proof as evidence.
"I think it's worse than physical assault. I know of a female conductor quite recently where she was spat right in the face - now that is absolutely disgusting."
Inspector John Clark, of British Transport Police, said: "This is a particularly nasty crime that needs to be stamped out, it is pleasing to see the commitment of management and staff.
"This is an anti-social offence which we are determined to combat."
A number of other rail and bus companies are now starting to use the kits.