Abstract :
Statement of size of N. Y. C. Lines telegraph and telephone plant and variety of engineering problems involved. Telephones used almost exclusively for train dispatching, not so general for message work, but growing. Automatic telephones used. Extensive local and long distance lines and switchboards. Telegraph system reaches all stations. Pole line is basis of plant, increasing in strength to meet safely the loads to which subjected. Railroad employs wire chiefs. Problems include electric protection, inductive interference, electrolysis, transmission, traffic, necessitating continual experiment and investigation. Telegraph answer-back used with selectors. Phantom telephone circuits used. Single wires for railroad telegraph obsolete, all wires used in simultaneous telegraphy and telephony. Extra high impedance telephone used for train dispatching. Iron wire joints welded. Battery consumption data; unit type switchboards designed, supplant dry battery for main selector ringing battery; chemical rectifier also used. Oscillograms of single-line telegraph current waves, when line insulation varies. Railroad long-distance lines can be loaded. Telephone selector current waves given. Gill local bell selectors used with repeat coil signaling to obtain low-resistance simplex. Duplex telegraph used on about 10,000 miles of circuit on N. Y. C. Lines. Polar duplex is approximate three-wire circuit. Self-balancing duplex designed especially adaptable at unattended repeater stations; oscillograms illustrating results in better balance of duplexes. No. 5-U retard coil of standard bridging duplexes and quads is auto-transformer as well as retard coil; is useful as retard, detrimental otherwise. Polar relay armature of differential duplex and quadruplex has more force than in bridging.
