See Q (29 Sep 13 - 08:18 PM) above:

Drilling by tarriers (paddies) took place on the Union Pacific transcontinental route, but only a fragment of a song exists. The song "Drill, Ye Tarriers, Drill," may have originated with this railroad or with the Central Pacific, long before the 1888 sheet music was published.

John P. Davis, 1894, The Union Pacific Railway, S. C. Griggs, Chicago. (Quoted from Norn Cohen, The Long Steel Rail.

The entire footnote in Davis reads:

Students of folk-lore will doubtless discover some substantial historical material in the refrain of song that the author has often heard sung by an old Irish friend – evidently having seen service in more than one campaign:

“Then drill, my paddies, drill,
Drill, my heroes, drill,
Drill all day,
No sugar in your tay,
Workin' on the U.P. Railway.”

[Davis, J.P., The Union Pacific Railway, (Chicago: S.C. Griggs, 1894, p.141, footnote I)]

The earliest “authentic work song” mention I've found so far is Davis' “old Irish friend.” In the following decades he'll get quoted in history books; children's novels and eventually the American cinema.

No mention of the Euro-American job title “tarrier” in professional industry sources so far. Mostly a French thing.