As part of its “Taking Questions” series, The Times’ City Room blog hosted Dennis Boyd, a TO along the 4 line last week. He answered three sets of questions about his job and his views on working underground (Part 1, Part 2 and Part 3). I found his answers very illuminating because it presents a view New Yorkers rarely see. We know that trains enter and leave stations; we know two people are responsible for their operations; but we don’t know why some express don’t wait for local trains or what the various markings and signal patterns mean. In Part 1, Boyd talks about the new automated announcements and how his job changed. In Part 2, he talks about why Lexington Ave. express trains crawl up and down the line at rush hour, and in Part 3, Boyd delves into train delays. Good stuff.