London Underground (LU) is to extend a scheme to pipe classical music into stations to deter yobbish behaviour.
Eighteen months ago, CD players were wired in to speakers at Elm Park, Hornchurch, Dagenham Heathway and Dagenham East stations.
Since then, instances of physical and verbal abuse have fallen by 33% and reduced the number of youngsters hanging around.
LU has now asked private Tube company Metronet to include 35 more stations.
Psychologists who have researched the link between music and behaviour say unfamiliarity is key to its success.
Metronet asset manager Nicky Spiers said: "It will not just be ticket halls that get the music as before but also waiting rooms where youths congregate and may cause trouble.
"We won't be linking this to platform speakers though - that's a captive audience and not everyone likes classical music."
John Strutton, of LU's crime and disorder unit, said: "We have evaluated the trial at Elm Park and this system does prevent youth disorder as part of a package of measures.
"That package includes more reassurance policing, greater staff visibility, physical changes to 'design out' crime, such as better lighting, and working with communities to provide better youth facilities elsewhere."
Eventually all stations across the network will have the capability of orchestrating their very own mini classical concerts through digital voice announcement systems which are being installed as part of the overall station upgrade programme.