Remember in October when we showed you a viral video of a dance party launched on a commuter train in Perth, Australia?

The same group who danced their way into the hearts of 40 million YouTube viewers has just followed up with shenanigans on another commuter train–this time a singalong.

On a wintery run of the 7:51 express train, they led passengers in a rendition of Somewhere Over the Rainbow in a bold attempt to chase away the Monday morning blues with a ukulele player keeping time.

Peter Sharp, the founder of the participatory arts group called it, "Easily one of the most uplifting experiences we've ever helped create."

The Liberators, as they call themselves–named for the sense of freedom they want people to feel when expressing themselves in public–have coordinated five different experiences on trains from story telling, to dancing, and singing.

"This is my full time job," Sharp told the Good News Network. "I am able to get paid doing DJ gigs that combine these acts of freedom at music festivals & family festivals and working with businesses to create interesting and ethically driven video content."

They recruited some of their own people to ride the train and help get the singalong started, but reported that around 60 percent of those on board were actual commuters.

Read more about their mission, and a crowd-funding campaign to bring their antics to trains in Europe on their blog.

(WATCH the heart-warming moments below)