Green’s Dictionary of Slang

1. (US Und.) transportation from one prison to another, the mode of transport is irrelevant.

1992

Bentley & Corbett Prison Sl. 9: Train Refers to prisoners being transported from one institution to another. (Archaic: boat, draft).

2. (N.Z. prison) a prison smuggler.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 193/1: train n. 1 an inmate whose job it is to smuggle goods in and out of prison.

3. (N.Z. prison) a marijuana cigarette conveyed between prisoners.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 193/1: train n. 2 a marijuana joint sent from one inmate to another after lockup, by being slid along the floor from one cell to another on a length of connected magazine pages.