I have studied British railways for most of my life and must say I have never come across any of the terms for wagons that you mention. I�ve even had a quick look among one or two of my (many) books and can find no trace. I�d be very interested if any other readers come up with anything.
The Jim Crow tool is a manual rail bending device. I�m not sure of its origin but, since it acts rather like a crowbar, it probably has something to do with that.
In another context, the term Jim Crow originated around 1830 when a white, minstrel show performer who would �black up� to look like a negro, danced a jig while singing the lyrics to the song, "Jump Jim Crow." As a result of this, the word Jim Crow (or Jimcro) became a racial slur synonymous with blacks or Negroes in the vocabulary of many whites. By the end of the 19th century acts of racial discrimination toward blacks in the USA were often referred to as Jim Crow laws and practices.