If you blinked, you probably missed a 'lost track' from The Beatles.

After all, it only lasts five seconds.

If you've ever seen the Fab Four's first film, 'A Hard Day's Night' (which is celebrating its' 50th anniversary this year), you may remember a scene with Ringo, a very uptight man, and a transistor radio, on a train.

(You can refresh your memory at the 4:00 mark of this video)

At the time, and in the five decades following the release of the movie, no one has given much thought into what exactly that song is, or, more importantly, who is performing it.

Until now.

It turns out, the song actually has a name - 'Train Music' - and the band playing it is none other than The Beatles themselves.

Dave Morrell, author of 'Horse-Doggin': The Morrell Archives, Volume 1' says the full song actually runs about 30 seconds and was found in a box called 'The Beatles.'

Another author, John C. Winn, in his book 'Way Beyond Compare', says the film's producer, Walter Shenson, verified in an interview that the song was done by The Beatles, in E major, with John Lennon playing a Chuck Berry guitar pattern and George Harrison on lead guitar. It was apparently recorded in soundtrack sessions before the first week of filming.

Isn't it amazing that just about the time you think there's nothing new you could learn about The Beatles, things like this pop up?