On the intermediate plane, or level, the real business of the passenger prefatory to his journey is transacted. The concourse, the great general waiting-room, with its subsidiary rooms for men and women, the ticket offices, and the telegraph offices are there gathered. From the roomy concourse, covered in steel and glass after the fashion of the famous train-sheds in Frankfort and Dresden, Germany, individual stairs and elevators lead to each of the track platforms. A sub-concourse, hung directly underneath the main structure, is reserved for exit purposes only, and serves to separate the streams of incoming and outgoing passengers. The north side of the station is separated and reserved for the use of the Long Island passengers, chiefly commuters. The theory of operation of the station is simplicity itself. A Pennsylvania through train from the West, after discharging its passengers and baggage, will not be backed out of the train-house, but will continue on through the station, under more tunnels and another river, to the storage yards just outside of Long Island City. Similarly, trains made ready for a long trip at the yards will proceed empty under the East River tunnels to the big station, where they will receive their outbound load. This is the theory of the station, an operating theory which makes it in part like a giant way-station and saves much terminal congestion. The Long Island trains and a few short-line Pennsylvania express trains will be turned in the station. These are the exception. Of interest fully equal to that of the new Pennsylvania Station, is the construction of a new Grand Central Station upon the site of and during the use of the old. The Grand Central Station, used by both the New York Central and the New York, New Haven, & Hartford Railroads, has been for many years New York's great gateway to the east as well as the north and west. It has developed a great suburban and a great through traffic since the construction of the first station--away back in 1871. Temporary relief was gained in the early eighties by the construction of an annex to the east of the original station. Still further improvement was gained ten years ago by tearing out a series of ill-arranged public rooms and substituting for them the single beautiful waiting-room that has proved so great a delight to travellers. Now that waiting-room is about to be demolished in the face of plans for the newer and greater Grand Central.