a couple more tidbits from IrTrad-L archives:
Another singer who has recorded this song is Len Graham, on his first album - "Wind and Water".
Joe Cooley recorded the jig instrumental under the title "Daniel O'Connell".
Another song usually sung with tune based on "Larry O'Gaff" is "The Humours of Whiskey" (stick to the craythur, the best thing in nature ...). That song is in the DT, but I haven't heard the audio and it says the tune is 'Top of Cork Road (Father O'Flynn)' ... the 'Father O'Flynn' I know is a different air than Larry O'Gaff. If you do an archive search for 'O'Gaff', you'' find that there are a handful of other songs in the DT that ARE said to go to the tune 'Larry O'Gaff'.

Mick Maloney is one singer/folklorist who says the muse was inspired by O'Connell's comment that the steam engine would be the making of future generations. O'Connell reportedly made the speech at the occasion of the introduction of the steam engine to Ireland. This steam engine travelled ~20 miles along the coast from Dublin to Bray.