premise: A middle-aged man works under the engine of a train on rail tracks.
hypothesis: A man is doing work on a black Amtrack train.
explanation_1: You can't infer he is doing work on a black Amtrack.
explanation_2: Just because a middle-aged man works under the engine of a train on rail tracks doesn't mean, he works on black Amtrak train.
explanation_3: The train could be a different kind of train than a black Amtrack train.
premise_logic: exists s1 x1 x2 x3 x4 x5 x6.(n_engine(x3) & a_topic(x1) & under(x1,x3) & of(x3,x4) & on(x4,x5) & n_track(x5) & of(x5,x6) & n_rail(x6) & n_train(x4) & n_work(x1) & of(x1,x2) & n_man(x2) & a_middle-aged(s1) & Theme(s1,x1))
hypothesis_logic: exists e1 s1 x1 x2 x3 x4.(on(e1,x3) & n_train(x3) & (x3 = x4) & ne_nam_amtrack(x4) & a_black(s1) & Theme(s1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_work(x2) & n_man(x1))