(S (S (S (NP (BASENP (DT A) (NN train)) (PRN (COMMA ,) (VP (VBG traveling) (PP (IN at) (NP (BASENP (DT a) (JJ high) (NN rate)) (PP (IN of) (BASENP (NN speed)))))) (COMMA ,))) (VP (VBD was) (VP (VBG carrying) (BASENP (QP (RB over) (NN 850)) (NNS passengers))))) (SBAR (WHADVP (WRB when)) (S (BASENP (PRP it)) (VP (VBD rammed) (PP (IN into) (NP (BASENP (DT an) (JJ empty) (NN train)) (PP (IN near) (BASENP (NNP Rio) (NNP de) (NNP Janeiro))))))))) (PERIOD .))