Slate provides here a link to a video on the machines used to operate the New York subway system. Much of this equipment dates to the first half of the 20th century. It's a great video. I had read about some of this before but never in this much detail.
The Slate columnist refers to this equipment "delightful, sure, but also deeply baffling." I think that this view misses a few points. First, modern computer equipment isn't always reliable in many aspects, ranging from computer security to electromigration. Second, much computer equipment isn't designed to last more than a few years. Replacing computers regularly is OK for data centers but it just doesn't work for a lot of infrastructure. Infrastructure has to be built to operate safely and reliably for years. Unfortunately, the computer industry isn't very good at designing things that last.
I find the video's discussion of the old-fashioned signaling system to be much more important than the age of the wires and relays. The old equipment can't identify the location of a train very accurately, which means that trains have to be spaced farther apart. One of the important benefits of new equipment and control system---known as CBTC---will be more efficient transit thanks to better location and control.