The N also has R40M's as well. R68A's run on the N and Q as well. There is no more R40M on the J/Z or M-the last left about a year ago.
Hey Rob: you don't like riding up front inside the tunnels!!?? That's a surprise! It may not be as scenic as outdoors, but viewing the signals, especially watching them changing in the distance is great underground. But I guess NYC tunnels seem dark and depressing compared to Boston's good tunnel lighting. That's why our trains use headlights! Chuckle!
Well, I actually got to see out front while underground just the other day, off of a Metro-North train and an R32 trainset. Although I prefer seeing thru on aboveground portions, its sometimes cool to see through in tunnels especially when the train is going wicked fast