Four men have been arrested in two separate incidents involving graffiti in the Illawarra at the weekend.
The first involved a citizens' arrest, when members of the public apprehended two men who sprayed graffiti on a wall on Flinders Street, Wollongong, about 9.45pm on Saturday.
Police Transport Command officers were called, and the men were found in possession of spray paint cans.
The two are yet to be charged, and inquiries are continuing.
In the second incident, police were called to Helensburgh Railway Station after two men were spotted in the rail corridor about 3pm on Sunday.
Officers from the PTC attended and stopped two men, aged 19 and 24.
During a search of the pair officers allegedly found and seized a large number of items, including spray cans and box cutters.
Both men were arrested and taken to Wollongong Police Station where they were each charged with multiple graffiti-related offences.
They were given bail to appear at Port Kembla Local Court in July.
The arrests came as the PTC celebrated its second anniversary.
Superintendent Bernie Ryan said police were more ready than ever to tackle crime on the Illawarra's rail network.
The command has notched up more than 5000 arrests across the Illawarra, greater Sydney and Hunter regions since its creation.
As overseer of police operations on the southern and south-west rail lines, Supt Ryan said officers overcame the "tyranny of distance" by working with local area command officers, as well as not being limited to catching trains.
He said information from the community about crimes on trains was vital for officers to continue their work.
"One of our biggest strengths is the ability to analyse intelligence coming from the community and police in order to deploy at the right locations at the right time," he said.
"That's our key, our ability to respond and identify crime trends, to address issues as they occur, and prevent them from occurring or escalating."
In addition to the weekend arrests, PTC officers recently arrested three men in relation to a graffiti attack in May when a train was stopped in Otford and a mural painted on one of its carriages.