This is leading to a lot of digression that really belongs somewhere else; here is more.
So far I have no 1840s British source for bulgine, only Bull Engine. The contracted term seems to be originally American. In the later 19th c. it is used by several English authors, including Rudyard Kipling in "Transfers and Discoveries."
However, invention of the term by blackface minstrels or railroaders is not the same as invention by Black Americans.

There are 19th c. examples of the word bulgine in newspapers and books beginning in the 1840s; I have given a couple, here are a few more. Unfortunately word searches of this kind are not easy. Only what is found online is easily available.

-"American Pictures Drawn with Pen and Pencil," Rev. Samuel Manning, Pub. London, 1876, Religious Tract Soc.
"Early on the second morning after leaving St. Louis, our train came to a sudden standstill, and a loud noise of escaping steam was heard from the engine. "Guess our bulgine's busted up," said my neighbour, a miner from New Mexico."

-Bulgine Mine, Clear Creek, Colorado- 19th c., but details not known.

-Cass City Chronicle, (California) 1881, article reprinted Dec. 20, 1935:
"'Twas Christmas time in Cass City... Give us your hand, brethren. Give us a genuine, old-fashioned handshake of congratulations.... We are going to have a railroad, we are, and don't you forget it. The bulgine will be snorting through this town in less than ninety days."

L. Carranco, 1962, "Logging Railroad Language in the Redwood Country." Only p.1 seen, jstor.org, American Speech v. 37 no. 2, pp. 130-136.

-"Po-ca-hon-tas," or The Gentle Savage," a play by John Brougham, opened in his theater, NYC, in 1855. John Smith & company raid the "Tuscarora Finishing School of Emancipated Maidens," where he meets Pocahontas. In an article in Jour. Soc. for American Music, R. L. Norris, 2007, mentions one of the characters in the play is killed by a bulgine. Not seen, so I don't have the citation.
The play and parts of it "remained a staple of theatre troupes and blackface minstrel companies for the next thirty years." Apparently great liberties were taken in succeeding performances; Wikipedia says "Dixie" and Zouaves were added for an 1860 performance in New Orleans.

I have put music hall and minstrel together in some discussion, I should have added theatre; they cross-fertilized and borrowed from each other. Opera and Shakespeare were not safe from the blackface minstrels, the plots and songs were widely parodied (Norris, J Soc Am Mus., 2007, vol. 1, no. 3, pp. 341-365; also the program "The Color of Shakespeare," can be heard here- http://www.soundprint.org/radio/display_show/ID/758/name/The+Color+of+Shakespeare

Commenting on Shakespeare performances in America, "Shakespeare productions attracted a broad audience across socioeconomic and ethnic lines, .....The plays were often accompanied by music, acrobatics, dance, magic, shows, minstrel shows, .... Shakespeare's most famous lines .....were parodied..."
http://www.shakespeareinamericancommunities.org/education/america.shtml