Looking at the NYC Lines it shows acq. by 1880 and dropped by 1892 -O5 . It has a draw bar instead of link and pin and I am not sure ,but I think they had to have draw bars by 1903 . LEW
Look how tiny the rail is! Today's rail just dwarfs that stuff. Awesome old photo's. Thanks for taking the time to post them!
The headlight is a more modern type, common after about 1900, the engine could have air brakes (hose on the pilot), although that could be a signal hose too. The car behind the engine is a combination car: coach, baggage, RPO. The headlights, drawbar and air hose could be retro-fitted to an older engine. The picture was probably taken in the early 1900's-1910's. The engine could be from the 1880's.