File:Electric railway journal (1918) (14574521640).jpg

Identifier: electricrailway511918newy (find matches)
Title: Electric railway journal
Year: 1908 (1900s)
Authors:
Subjects: Electric railroads
Publisher: (New York) McGraw Hill Pub. Co
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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ut they can be worked up later shouldthe proposed spirals be considered worthy of furtherstudy. Co-ordinates for the center line are given inthe table for convenience in plotting for com-parison with other spirals. These figures were obtainedby scaling from layouts plotted on a scale of 1 in. =1 ft. by deflection angles and chords. The precise radiiof these spirals can probably be modified slightly toadvantage, as stated below, but the writer believes thatthe general scheme submitted deserves careful consid-eration both as to the fundamental basis of the indi-vidual spirals and their group relationship. All the spirals are suitable for easements for plaincurves and their number and relative proportions al-low considerable variation to suit local conditions. Inall cases circular arcs of the standard switch radiishown can be cut in without any change in the spiraland of sufficient length to take switch pieces of A. E.R. E. A. standard length. 650 Electric Railway Journal Vol. 51, No. 14
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April 6, 1918 Electric Railway Journal 651 The proposed standards provide three spirals intowhich 100-ft. switches can be cut, two into which 200-ft.switches can be cut, and one spiral which can be usedas an easement for a clearance curve for 200-ft.switches or as a short spiral into which a 75-ft. switchcan be cut. Spiral 100-A is intended to be the shortest spiral ofthe given type which will allow the cutting-in of a stand-ard A. E. R. E. A. 100-ft. radius switch. As shown, it isa little longer than absolutely necessary and the radiican be figured down accordingly if desired. Spiral100-B is of 25 per cent greater radius and spiral 100-C ENGINEERING DATA FOR PROPOSED UNIFORM SPIRALS SPIRAL 200 CN=l. L = 20. R=35. D=4° 6. Co-ordinates, 17588584435 Dp Cp hp X Y 0° 00 0°00 0 0 0 0.00 0° 49 1°38 5 0 1 5 00 2° 03 4° 55 10 0 4 10.0 3° 50 9° 50 15 1 0 14.9 6° 09 16° 24 20 2 2 19.S SPIRAL 100 BN=9. L=45. R=35. D=i° 6. Co-ordinates. SPIRAL 200 A#=15. L = 75. fl=50. £=2 52. Co-ord

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