You did not see the train operator (motorman) look out the window because on most trains there is a conductor (doorman, guard) half-way back in the train. As the train arrives in the station, he drops his window and waits for the train to stop with him opposite a striped board. He then points to the board (acknowledging that the stop is correct, with neither front nor rear hanging off the platform), and he opens the doors. I have been told that in closing the doors he first looks rearward and closes those doors when they are clear, then looks forward and safely closes those. I believe he is required to observe the platform as the train leaves, but sticking one's head out while the train is moving could prove fatal.
----
A ten-car train has the conductor at the forward cab of the sixth car. As a generalization, our equipment is now formed in four-car or five-car sets, and the conductor would be wherever the set meets. In some places the conductor is assisted by tv screens at the striped board.
----
On certain routes, there is OPTO (one person train operation). I'm uncertain whether every stop on those routes has a tv screen adjacent to the operator's position. Most of the OPTO trains are half the length of regular service. I believe that the L line, which uses 8 60-foot cars regularly has new screens at the operator's stopping point.
----
When people argue that one-person operation is the norm on other systems, such as Paris, I point to the 600-foot length of many trains. Of course, the TA wants to go to full OPTO, but they are introducing it first on trains with short trains.
----
When I guide strangers about our town, I show them the striped boards that indicate the conductor's position on most routes. For safety, I would urge a person to board a car near that position or anywhere from the front to the conductor's position. At least in years past, the rear car was the "club car" of rude conduct.
----
The oddest situation is at the 42nd St shuttle where OPTO was introduced as two-person one-person operation. An operator is stationed at each end, acting as operator in one direction and as an over-qualified conductor the other direction. I don't know if it's called TPOPTO.
----
All the above is subject to correction by more knowledgeable people.
Joe