Green’s Dictionary of Slang

(US) to associate with, to cooperate with.

1871		J. Hay ‘Banty Tim’ in Pike County Ballads 22: It gravels me like the devil to train Along o’ sich fools as you.
1907		Methodist Rev. Nov. 984: He does not train with the extreme radical theologians [DA].
1922		S. Lewis Babbitt (1974) 24: Now Myra is going to get pathetic on me because we don’t train with this millionaire outfit.