Rapid Transit Station Design (1920)
Electric Railway Journal · Vol. 56, No. 19 · November 6, 1920 · pp. 966-968.
Rapid Transit Station Design. Relation of Platform, Entrance and Exit Arrangement to Passenger Interchange, with Appropriate Examples from Typical Subway and Elevated Stations for Rapid Transit Lines.
In the issues of Engineering News-Record for Oct. 28 and Nov. 4 Olof A. Nilsson, designer, Transit Commission of New York City, gives a comprehensive analysis of the problems connected with the design of stations for rapid transit lines and illustrates present practice by means of appropriate examples. Some of the points made by Mr. Nilsson are outlined in the following paragraphs:
Two factors determine the passenger capacity of a railroad, the capacity of each train and the minimum headway on which it is possible to operate trains. The former, of course, depends on the capacity of each car and the number of cars in the train. The minimum operating headway is determined by one of two independent factors, the safe minimum distance between trains running at a certain speed between stations, "the running headway," and the time required by the train to pass through a station block, "the station headway." The station headway, again, is primarily determined by the length of the train stop at the station. As ordinarily constructed the stations are the points of slow train movement, and, in general, the station headway governs, and the minimum operating headway is fixed by the maximum station headway on the line.
When a station is planned the starting point should be the ultimate carrying capacity of the line and the ultimate traffic yield of the district tributary to the station. From these factors and from the general scheme of operation the size and capacity of the cars and the number of cars to the train, the train lengths and train capacity, are determined. The train length is the basis for the platform length, while the width of the platforms, the width and capacity of stairways and passages, etc., are fixed with reference to the anticipated maximum traffic flow through the station. This is seldom a simple problem.
Classified on the basis of platform type, all stations are of either the side-platform type, the island-platform type, or a combination of both. With reference to location relative to the line, stations may be classified as:
(a) Terminal stations, which may be either the loop-end type (Hudson & Manhattan downtown terminal in New York) or the dead-end type (Brooklyn Bridge terminal New York).
(b) Intermediate stations.
(c) Stations at junction points, where two or more lines meet, or where one main line divides into branches.
(d) Stations at crossing points, where two or more lines cross, either with or without track connections.
In planning entrance and exit stairways it makes a difference whether the station is elevated or underground. In crowds more people go up a stairway than down in a given period. A convenient and safe rule in figuring the capacity of a stairway is to allow for each lineal foot in width 1,000 people per hour for downward and 1,100 for upward movement when the movement is all in one direction. The capacities of unobstructed ramps and passages may be assumed as 2,000 per lin.ft. in width per hour. For an average walking speed of 5 ft. per second this allows 9 sq.ft. of floor space to each person. Where people move simultaneously in opposite directions under crowded conditions the capacity is less. No stairway planned for simultaneous movement in both directions should be less than 5 ft. wide. Sharp turns also seriously retard the movement and should be avoided wherever possible. The maximum grade for a ramp should be 11 per cent; 8 to 10 per cent is better. For stairways the pitch adopted in the New York subways 7 in. rise and 11 in. tread is good; when conditions permit, it is desirable to reduce the height of the riser and correspondingly increase the width of the tread according to the rule that two times the height plus the width (both in inches) should equal twenty-five.
On a loading platform passengers waiting for a train naturally group themselves along the platform edge. Sufficient width should be allowed for these waiting passengers to permit a certain freedom of movement and to give unobstructed passage to incoming passengers. Moreover, behind these groups there should be enough width to permit people to move about between different parts of the platform and the platform stairways. Each station is an individual problem and no definite rule for platform width can be given, except the general statement that the more the conflicting passenger streams are separated into definite channels and the quicker the platform is cleared the better will be the result.
SOME EXAMPLES OF SUBWAY AND ELEVATED STATIONS ARE CITED
In the Paris rapid transit system the lines all have loop ends, permitting the trains to run continuously back and forth and around the loops without the use of switches and crossovers. For the most part these lines are built underground with stations as close to the surface as the method of construction and the topographic conditions allow. The standard platform length is 246 ft. and the width (of side platforms) about 13.5 ft. Intermediate stations are generally of the side-platform type, while most of the end stations have island platforms. The latter have also, in general, separate stopping places for loading and unloading, so that incoming and outgoing passengers are kept separate from train to street.
On one of the additions to the rapid-transit system of Berlin, the Schoneberg subway, a two-track line which was opened for traffic in December, 1910, the stations, of the island-platform type, have platforms 25 ft. wide and entrances at the ends through stairways 13 ft. wide to the middle part of the street. They were planned to be built in two stages, the first part of it only was designed to be completed at the opening of traffic, the second part to be added when necessitated by the growth of traffic. The first part of the station, with a platform length of 148 ft., accommodates a train of three cars; the completed station has a platform 312 ft. long and accommodates a seven-car train. The middle part of the platform is occupied by various stands and enclosures for station attendants, newspapers, etc.
In Boston the busiest station on the subway system is the Park Street underground station at the intersection of the Tremont Street subway and the Cambridge-Dorchester tunnel. Here the lower level station, for Cambridge-Dorchester trains, is 350 ft. long and has two side platforms for unloading and one island platform for loading. The former are 10 to 12 ft. wide, the width of the latter varies from 18 to 30 ft, tapering from the center toward the ends. The upper level for the Tremont Street surface cars has two island platforms. Each track has berths for eight cars along the straight portion of the platform. The east platform (exclusive of stairways) contains about 9,625 sq.ft. and the westerly one about 14,050 sq.ft. The entrance and exit stairways from the upper level to the surface are through structures on the Boston Common. The southerly entrance on the easterly platform has an intermediate lobby or mezzanine above the platform for the control; on the other entrances the control is on the platform. The lower level has an entrance lobby at its easterly end just east of the Park Street structure with stairways to the street and from the unloading platforms, ticket control and a wide stairway to the loading platform. From both unloading platforms there are escalators to the street surface. For direct transfer between the two stations there are six stairways, one from each platform on the lower level to each one on the upper.
An extensive rapid transit system including both subways and elevated roads has been planned and is being built in Philadelphia and the stations on this system are good examples of modern, well planned, rapid transit stations. In the Girard Avenue express station on the Broad Street subway the platform length is 550 ft., the width at the center 20 ft. 9 in., tapering toward the ends through a large radius curve on the outside platform edge. The platforms are accessible from the street through a mezzanine under Girard Avenue which has eight stairways from the street and three to each platform. In addition there are stairways for exit only, near the ends of both platforms.
A local side-platform station on the same line at Ridge Avenue has a similar arrangement with entrances and exits at the center and additional exits near the ends. The platforms, 12 ft. wide except at the ends, where the width is 10 ft., are unobstructed through their entire length, platform columns being eliminated and the stairways being built in recesses outside of the walls of the main structure. Another local station at Twelfth and Arch Streets on the "delivery loop subway" has entrances at or near the ends with additional exits at the center.
The Brooklyn Bridge station of the first subway in New York, opened for traffic in 1904, was built for eight-car express trains with platforms about 350 ft. long. The width of the express platform at the center is 20 ft., narrowing toward the ends. The stairways from the platforms are 8 ft. wide and the mezzanine platform or bridge spanning the tracks is 20 ft. wide. The two side platforms of the station have never been used. When the rapidly growing traffic made the train service originally adopted insufficient, the express platforms were lengthened to 480 ft. and ten-car express, trains put in service. A ten-car train is 520 ft. long, so that the end doors of the first and last cars do not come within the platforms and are not used.
FIG. 1 SIDE-PLATFORM STATION. FIG. 2 SIDE PLATFORM STATION WITH MEZZANINE. FIG. 3 ISLAND PLATFORM STATION.
The Chambers Street station of the Seventh Avenue subway, opened in 1918, is located not far from the Brooklyn Bridge station and invites a comparison with the latter. The platforms are 18.5 ft. wide and 485 ft. long. Instead of a narrow bridge spanning the tracks there is a large mezzanine floor under the intersection of Greenwich and Chambers Streets with stairways to the four street corners. From each platform there are four stairways to the mezzanine. Should additional stairways and mezzanine area be required the mezzanine can be extended over the platform in both directions.
A station that by virtue of its location is destined to have a very heavy traffic is the Grand Central station of the Park Avenue-Lexington Avenue subway, opened for traffic in August, 1918. It is located diagonally across Forty-second Street between Park and Lexington Avenues, and is adjacent to and by means of underground passages connected with the New York terminus of the New York Central and the New York, New Haven & Hartford railroad systems and the Grand Central Terminal. Directly below the station and connected to it by means of a ramp, a stairway and three elevators is the Grand Central station of the Queensborough subway, which here runs under Forty-second Street. There is also a shuttle service under Forty-second Street from this station west to the Times Square station on the Seventh Avenue line. It is evident that in addition to the traffic originating in the neighborhood, rapidly being built up with large office structures and hotels, an unusually large transfer traffic will result from the meeting and intersection of these traffic lines. The station is of the ordinary type for four-track express stations with two island platforms of varying width about 485 ft. long. Each platform has, in addition to two stairways leading down to the passageway and ramp communicating with the Queensborough station below, six stairways leading to two mezzanine floors above the platform. From these mezzanine floors there are numerous passages and stairways leading through adjacent buildings to the street level and opening on Forty-second Street, on Park and Lexington Avenues and as far north as Forty-fifth Street. A short ramp connects the larger of the two mezzanine floors with an island platform serving the shuttle trains to the Times Square station.
The problem of locating entrances and exits is frequently a difficult one for the station designer. On a busy street the presence of an elevated stairway or a subway kiosk on the sidewalk is, as has been demonstrated in New York, a serious impediment to the movements of pedestrians. On the other hand a subway or elevated entrance located entirely inside the building lines of an adjacent business building not only has the virtue of not being a sidewalk encroachment but is also an actual asset to the owners of the building, increasing in value as the traffic increases. This has also been demonstrated in New York, where property owners in general are alive to the advantage of having a subway entrance on the premises, and are quite willing to grant the space for and pay the cost of an entrance without any other compensation than the resulting increment in rental value.
In the building of the Frankford elevated railroad it was aimed to avoid placing the station stairs on the sidewalks. At all stations on this line a building containing stairways, control, toilets and waiting room has been built within the building lines on property taken for the purpose under condemnation proceedings. At the platform level there is a bridge from the station building to the platform. Such a station is located at Ruan and Church Streets. It is a rectangular building and control may be at either the street level or at the platform level.