File:Electric railway journal (1913) (14571764179).jpg

Identifier: electricrailway411913newy (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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Draw, Motor-Operated Track Bumper and Block Signal Approaching Draw that it would have been troublesome to free it from snow, newal and attachment of ties would have presented grave although incidentally the saving in weight by using the type difficulties. In the construction adopted, in which steel of open floor adopted was of great advantage in reducing I-beam stringers were embedded in concrete, a standard the load upon the foundations. On the bridge proper the elevated railway floor system was made possible. The 364 ELECTRIC RAILWAY JOURNAL (Vol. XLI, No. 9. foundations are of concrete carried on 5790 wooden piles.The bridge is 31 ft. wide between piers. On account ofthe failure in the Boston district of concrete exposed to saltwater it was decided to face the piers with granite from agrade 2 ft. below mean low water to a point 5 ft. above thefinished roadway on the dam. Above this finished gradethe superstructure is of reinforced concrete made of / v 1 t M-7f : : \-m-7$- J 1 ^-i
Text Appearing After Image:
in a vertical position, the reinforcement being attached tothe iron pole itself. Wooden suspension braces are usedon the catenary section. The messenger cables are of5/16-in. steel and stranded. At each span a ^-in. cross-suspension steel cable is used. The trolley is suspendedabout 18 ft. above the rail with both types of construction.On the ordinary overhead trolley section of the extensionthe span between successive cross sus-pensions is about 50 ft. Where thedraw occurs the trolley wires are sup-ported by a pantograph which folds upwith the draw and is designed to keepthe trolley taut at all times. Thepantograph is composed of 2-in. extraheavy wrought-iron pipe framing withmalleable-iron swiveled ball fittingsand cross bracing of %-in. diagonal \ Boston Improvements—Pantograph Mechanism on Draw Span of the Charles River Bridge crushed Chelmsford granite and granite dust. The elevatedstructure on the extension is carried over Prison PointStreet, the tracks being supported by four

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