. The Street railway journal . ft., while thecenter height is 16 ft. 10 in. The arch is 24 in. thick at thecrown, and the bench walls are 4 ft. thick. Unlike mosttunnels of this type that have been built the invert is per-fectly flat, having a thickness of 2 ft, exclusive of theconcrete in which the track structure is imbedded. Thetunnel section proper required cu. yds. of concrete perlinear foot. The details of the-reinforcement of the tunnel sectionare shown in an accompanying illustration. The arch has 422 STREET RAILWAY JOURNAL. [Vol. XXX. No. 12. two sets of lj^-in. round rods,
. The Street railway journal . ft., while thecenter height is 16 ft. 10 in. The arch is 24 in. thick at thecrown, and the bench walls are 4 ft. thick. Unlike mosttunnels of this type that have been built the invert is per-fectly flat, having a thickness of 2 ft, exclusive of theconcrete in which the track structure is imbedded. Thetunnel section proper required cu. yds. of concrete perlinear foot. The details of the-reinforcement of the tunnel sectionare shown in an accompanying illustration. The arch has 422 STREET RAILWAY JOURNAL. [Vol. XXX. No. 12. two sets of lj^-in. round rods, alternating with girder rails,all of which are spaced as shown. The rods in the sidewalls have their lower ends imbedded in the invert, andextend up into the arch, overlapping those in the latter toproduce continuous reinforcement. The invert is rein-forced with two layers of old rails, placed rails in the lower layer are ft. long and are placed4 ft. apart on centers; those in the upper layer are 28 VIEW SHOWING THE RETAINING WALLS long and are 12 in. apart on centers, their tops being 1 the surface of the invert section. The tracks in the tunnel have 80-lb. T-rails attached tocreosoted ties with screw spikes. The ties and rails areimbedded in concrete to within 1% in. of the top of theball of the rail, the concrete being finished to a smooth sur-face to form the floor of the tunnel. The floor between therails of each track is practically flat, transversely with thetunnel, and between the tracks is depressed only slightly to-ward the center line. Connections to a drain are made atintervals of 200 ft. in the tunnel so the floor can readilybe flushed clean, thus avoiding any difficulty from dust, orodors from refuse that would collect in stone ballast. Atthe same time the track structure is believed to be of suchdesign that the concrete in which it is embedded will nothave to be disturbed for a long period. A 15-in. sewer pipe was laid under t
Size: 1855px × 1346px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
