Hadn't thought of this one for quite a while, but it's time to start singing it again! I learned it in high school, probably from the Marais and Miranda record. It's published in their book "Folk Song Jamboree" (1960, pp 72-3). I still have my Ballantine Books paperback (yellowed, but pretty much intact) which cost all of 50 cents at the time.

Their introductory notes help explain why the song was known in England and Scotland and Australia -- and South AFrica, where Marais and Miranda presumably learned it-- but wasn't widely known in the States. They read:
"American origin. In 1897 the "Scottish Student's Song Book" published this tune, the lyrics by an American, Louis Shreve Osborne, who graduated from Harvard in 1873 and was living near Edinburgh for six months' study. The song collection had a wide circulation and "Bangor" became popular throughout the British Empire before it was known in America. Osborne's poem was based on an earlier one by John Godfrey Saxe, "Rhyme of the Rail," written in 1849. The melody of Osborne's published song was a development from a "Railroad Chorus" issued in Philadelphia in 1854."