. The Street railway journal . FIG. -DUPLICATE PIPING WITH EQUAL SIZED MAINS INCONSTANT USE—PLAN AND ELEVATION. No. 7. The latter costs about eighty per cent morethan the single and seventy per cent more than thesmall duplicate system No. 8. In .system No. 5 the mentioned in .systems No. 6 and No. 7 is avoided,since some part of both sides of the plant are presumably infrequent use. The drop in steam pressure is more than inany other system, due to the great length of mains re-quired. The is large, due to the fact thatthere is a greater superfici
. The Street railway journal . FIG. -DUPLICATE PIPING WITH EQUAL SIZED MAINS INCONSTANT USE—PLAN AND ELEVATION. No. 7. The latter costs about eighty per cent morethan the single and seventy per cent more than thesmall duplicate system No. 8. In .system No. 5 the mentioned in .systems No. 6 and No. 7 is avoided,since some part of both sides of the plant are presumably infrequent use. The drop in steam pressure is more than inany other system, due to the great length of mains re-quired. The is large, due to the fact thatthere is a greater superficial area in this systemthan in any other. It also forms a particularh- bad layoutfor future extensions, since any extension of building in theline of a main places boilers and engines farther apart. 424 STREET RAILWAY JOURNAL. [Voi,. XII. No. The advantages of the small duplicate sys-tem No. 8 are as follows: (I) Its low first cost which is only ten percent more than that of the single system. (2) Itsreliability. (3 ) Its economy of operation. (4) Itsadjustability and convenience in repairs. With reference to the reliability of this sys-tem it may be said that it reduces the chance ofcrippling the service of the piping plant just fiftyper cent. All gate valves are in use and open allthe time, thus preventing their being seated. Inthis way a pipe or main may be thrown out atany time and the load transferred to the otherside without stoppage or delay. The drop insteam pressure when one side alone is used canbe quickly made up at the boilers by increasingtheir pressure. So far as economy is concerned this systemhas oi^ly forty per cent greater superficial areathan the single system and thirty per cent lessthan the large duplicate system, and, as previ-ously explained, the drips from each side of thissystem are pump-returned t
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
