train, v.² — Green’s Dictionary of Slang

train v.²

[pull a train under train n.¹ + an undertone of SE train, to teach (one) disciplined behaviour. This is not gang rape as such, since the woman is ostensibly willing, but she may in reality have little option but to accede. Originated during a well-publicized incident at Ingham, N. Queensland in 1977; but note train n.¹ which predates it]

of a man or men, to indulge in group sex with a single woman.

1976		National Times 29 Nov. 10/2: How women are trained. If it’s not rape what is it? [AND].
1983		G. Lewis Real Men like Violence 81: The notorious gang rapes which occurred [...] in 1977 were based on this kind of male bonding. Gang rape there was referred to as ‘training’ the local girls [AND].
1994		N. McCall Makes Me Wanna Holler (1995) 44: Scobe and his boys trained anybody they could get their hands on.
1997		G. Sikes 8 Ball Chicks (1998) 115: They train their girls [...] not everybody, just the leaders. Two or three guys.

train v.2

train v.²