516 BEI.L SYSTEM TECHNICAL JOURNAL 



during normal coiiditions, but also during emergencies, when it has 

 been possible to tiuickly assemble equipment or materials from any 

 part of the sNstem and promptly restore or expand the service as 

 required. 



Important engineering problems of great variety, therefore, present 

 themselves on every hand calling for consideration by the engineers 

 in the General Engineering Departments, as well as the Traffic, Plant 

 and Commercial engineers associated with the operating divisions 

 of tlic companies. 



I'l .\NT Extensions to Meet Service Requirements 



A very large part of the engineering work of the Bell System is 

 concerned with the design of plant extensions to meet expected future 

 service requirements with the maximum economy consistent with 

 maintaining the service standards of the s>stem. I shall not discuss 

 the magnitude of the various activities and requirements of the 

 system, but will recall to your mind a few of the outstanding items 

 to better illustrate the magnitude of this part of the engineering work. 



Telephone stations are being connected at the rate of over two and 

 one-quarter million annuall>-. 



The resulting net additions or gain in stations i)er year is approxi- 

 mateh' 800.000. 



To meet this station gain and to replarc (■(iiiipnient remoxed from 

 plant, switchboards are being adtied at the rate of approximately 

 l,2(J0,000 station capacity annually. 



The Bell System installs in one year approximateK 30 billion feet 

 of insulated conductor in lead covered cable ranging in unit sizes from 

 1 pair to 1,212 pairs. Of this amount, more than 27 billion conductor 

 feet constitute the net annual increase in conductor mileage. 



The above plant additions, together with other important items, 

 such as poles, wire, etc., involve a net increase in the telephone plant 

 of nearly three hundred million dollars annually. 



It is of interest to note, in this connection, that the annual additions 

 to the telephone ]ilant to(la\' are e(iui\alent to the entire plant in 

 service in ilu' Bill System as ol aiiout 20 to 2.") \ears ago. 



Necessiiv ii>k .\i)\ANn-; I'i.anninc 



Obviously with a program of this magnitude and of such diversity' 

 in the character of its related units, careful advance planning is neces- 

 sary to insure economical and satisfactory performance. 



