Perhaps the tracks were more reliable in ye olden days because they were not so old back then. The NYC subway system still runs largely on technology from the 1930s. Much of the switch infrastructure still runs on vacuum tubes. Maintenance was heavily neglected in the late 20th century, ridership is way up, and repairs are challenging to schedule on one of the world's only 24 hour subway systems. Maybe if NYC of your time hadn't coasted on the investments of the early 20th century, your train wouldn't be so late.