An amazing chemical sensor on Sydney trains is catching vandals in the act when they spray graffiti

One of the graffiti vandals captured during the Mousetrap trial

A trial of new technology that senses when spray paint or permanent markers are being used on trains in Sydney has seen more than 30 people arrested for graffiti crimes.

The trial, dubbed “Mousetrap”, uses electronic chemical sensors fitted in the carriages. When it detects the vapour from spray paint and marker pens, it triggers live CCTV recordings that are sent directly to Sydney Trains staff and Police Transport Command are sent to intercept the people responsible.

Sydney Trains CEO Howard Collins said $34 million was spent on removing graffiti last year – an increase of $30 million on the year before.

“Our customers hate it – it’s one of the top customer complaints and cleaners work hard to remove about 11,000 tags from trains each month,” he said.

“We know it’s early days for Mousetrap but its success has been in allowing Sydney Trains to move from a strategy of removing graffiti to one where we stop it as it happens.”

NOW WATCH: Briefing videos

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.