WordNet (r) 3.0 (2006):

training school
    n 1: a school providing practical vocational and technical
         training
    2: correctional institution for the detention and discipline and
       training of young or first offenders [syn: reformatory,
       reform school, training school]

Moby Thesaurus II by Grady Ward, 1.0:

47 Moby Thesaurus words for "training school":
   POW camp, bastille, black hole, borstal, borstal institution,
   borstal school, bridewell, brig, cell, concentration camp,
   condemned cell, death cell, death house, death row, detention camp,
   federal prison, forced-labor camp, gaol, guardhouse,
   house of correction, house of detention, industrial school,
   internment camp, jail, jailhouse, keep, labor camp, lockup,
   maximum-security prison, minimum-security prison, oubliette, pen,
   penal colony, penal institution, penal settlement, penitentiary,
   prison, prison camp, prisonhouse, reform school, reformatory,
   remand school, sponging house, state prison, stockade, the hole,
   tollbooth