(S (S (BASENP (DT The) (JJ empty) (NN train)) (VP (VBD was) (PP (IN in) (NP (BASENP (DT the) (NN process)) (PP (IN of) (S (VP (VBG being) (VP (VBN moved) (PP (IN between) (NP (BASENP (NNS sets)) (PP (IN of) (BASENP (NNS tracks))))))))))))) (PERIOD .))