【中国科学社论文专刊】一 - 中国科学社中国科学社.pdf
後新编英文世界地理 GEOGRAPHYOFTHEWORLD By R)Wolcott .2copy A geography that gives the most up-to-date facts of the newworldwelivein.Simple and accurate,it presents the politicaland commercial developments from the Chinese standpoint in a very fascinating manner.
SIGNAIING AND INTERLOCKING involved and where all switches and signals come within a radius of approxinately 1,00o feet.The power or forco which actually moves the switch or clears the signal is provided by a man puiling the various levers in this type of macbine.
SIGNALING AND INTERLOCKING would not have you understand that the automatic signaling f the single track will give as great traflic facility as double racking,but the point is that by automatic signaling the single aek,trafiefacilities can be increased tomeetrequirements for a iong timc and thereby