The Thomas & Friends episode "Jack Jumps In", when released in the US in 2004, was released on the DVD/VHS "New Friends for Thomas". This DVD/VHS was unique in that it was the only DVD/VHS to be narrated by long time UK narrator Michael Angelis - this release being in-between the hiring of Michael Brandon and the leaving of Alec Baldwin as narrator in the US. This episode along with "A Friend in Need" were narrated by Alec Baldwin, however for consistency reasons, Michael Angelis' UK Narration with some dialogue redubbed by Angelis were included.
The original Alec Baldwin narration for "Jack Jumps In", along with "A Friend in Need", was last heard when the whole episode was shown on May 16, 2006 on TVOntario in Canada.  Two recordings of the episodes from this airdate had popped up on YouTube in '06, before being privatized in 2007. These uploads were both of exceedingly poor quality, being filmed in front of a TV.
"A Friend in Need", the second part of this episode, was released with Baldwin's narration on the DVD "Mud, Glorious Mud" on May 6, 2008. However, "Jack Jumps In", despite being the first part of the story, was never given an official release with Baldwin's narration, or has shown up through any fan recordings online.
7/5/14 On this day, Baldwin's narration was uploaded to Dailymotion, albeit in low quality (by which we mean recorded off a television by
10/5/14: On this day, a higher-quality version of Baldwin's narration was uploaded on YouTube by TTTEArchives.
6/18/14: Audio has been uploaded to YouTube by thomasultimate1213 from the last time the episode aired on TVO after the station switched to airing CGI episodes.