Non Revenue.
New York City Transit Authority (NYCTA) TGC4 has just emerged from the tunnel under East New York, passing the former East New York station, which closed in 1924. The TGC is working its way back from Jamaica, having overnighted there after inspecting the tracks of the East Side Access tunnels. The subway inspection car was needed for this as LIRR's inspection cars do not fit on the line due to the low overhead clearances in the 63rd St Tunnel.
Also of note are the insulators hanging from the apex of each tunnel portal; the Bay Ridge Branch was the only LIRR branch electrified with overhead catenary, as it was primarily served by New Haven Railroad freight trains via the New York Connecting Railroad (as is inscribed on the top of the tunnel).