From the Guardian, "Comment is Free" Ariane Sherine: All aboard the atheist bus campaign
"The atheist bus campaign launches today thanks to Comment is free readers. Because of your enthusiastic response to the idea of a reassuring God-free advert being used to counter religious advertising, the slogan "There's probably no God. Now stop worrying and enjoy your life" could now become an ad campaign on London buses – and leading secularists have jumped on board to help us raise the money.
The British Humanist Association will be administering all donations to the campaign, and Professor Richard Dawkins, bestselling author of The God Delusion, has generously agreed to match all contributions up to a maximum of £5,500, giving us a total of £11,000 if we raise the full amount. This will be enough to fund two sets of atheist adverts on 30 London buses for four weeks"
Note, unlike the buses in the UK, the trains of Sodor celebrate Christmas. I don't know if Jesus died for their sins too.