Sound Tracks festival hits London's Overground
It is the unwritten rule obeyed by London's commuters - do not engage your fellow travellers in conversation, and refrain from prolonged eye contact.
But a one-day festival on the capital's Overground network on Saturday is shaking passengers out of their self-imposed isolation.
Sound Tracks, which ran as a trial in 2011, will stage musical performances within train carriages on the line between Dalston Junction and Peckham Rye.
The "travelling stage" will host over 40 acts between midday and 20:00 BST.
Fabian Holland, a solo musician who played the festival two years ago, said he initially received mixed responses from passengers, but managed to win most people over.
"People were very surprised to see musicians play on the actual train," he said. "The experience was quite daunting, but it got people talking."
Fabian's brand of folky acoustic music made him difficult to notice in a rowdy carriage on a Saturday night, but the timing had its benefits.
"It helps when people have had a drink or two," he said.
Indeed, seeing people "come out of their shell" is one of the festivals aims, according to Sound Tracks' art curator, Kasia Maciejowska.
The event, which is being staged with the approval of Transport for London (TfL), will "give people a more positive experience of London transport," she said.
It's not all about the music acts, either.
Theatre company Dumblove Encounters will be recreating scenes from famous movies, such as Sliding Doors and North by Northwest, in which lovers meet on a train.
The performances will be staged as subtle conversations between two "regular" passengers, tempting cine-literate travellers to identify the film scene.
The company will also later try to get as many people as possible on a single train to play charades.App 'treasure hunt'
"We've done this before for our own entertainment on the Tube network", said cast member Jack Cole.
"The best thing is that when we leave the train it carries on without us. It's our little theatrical legacy."
Not satisfied with bringing music to the train network, Sound Tracks is even bringing regulation station signs to life.
A smartphone app developed specially for the event by designers Saint-H will give users the chance to access exclusive content by pointing their camera at place names and station posters.
"It's a bit of a treasure hunt," explained Nicholas O'Donell-Hoare, who helped design the app.
Festival-goers who use the app to take a photo of the station sign at New Cross, for example, will be directed to a video of indie band Bloc Party, who originated from the area.
"We will be giving people hints on Twitter," added Mr O'Donell-Hoare.
The festival will also take place in more stationary environments, such as the Dalston Roof Park and the Bussey Building in Peckham.
Sound Tracks will be using the shaft of the Brunel Museum in the Old Docklands, where Isambard Kingdom Brunel began his career, as a performance space.
"The festival is all about being in the moment," said Kasia. "Hopefully it will make us all more communicative."