On January 12 1967, The Beatles entered studio 3 at EMI Studios in order to add extra instruments in the creation Paul's "Penny Lane" masterpiece. McCartney decided it would suit the song to have some extra sounds on it and so it was that this afternoon/evening session saw additional outside musicians perform at Studio 3 (the smaller one).
The instruments used for the solo part of the song consisted of having trumpets in the choruses, two oboes and two cor anglais used during the solo gap and at the last chorus as well. A double bass was also added on to the last verse of the song. All of the woodwinds/brass overdubs were added to track 2 of the four track recording.
At the end of the session, the song was mixed for mono and entitled RM8 (remix 8). This includes the overdubs explained above and it is before the Bach trumpet was added days later.
This version of the song can be found on some bootleg CDs including the title "Turn Me On, Dead Man: The John Barrett Tapes".
I've included this mix version from the "youtube" site for your listening pleasure.