Abstracts of Technical Articles by Bell System Authors 



Recent Developments in Burying Telephone Cables} Donald Fisher 

 and Temple C. Smith. The term "buried cables" has come to mean those 

 underground cables which have no conduit protection. Due to the ac- 

 celerated demand for such construction in recent years, much eflfort has 

 been expended in devising methods and developing machinery for burying 

 cables. One of the earlier methods used in this and some foreign countries 

 was to dig a trench by hand alongside the road; unreel the cable from a 

 moving truck, thus laying it beside the trench ; work the cable over into the 

 trench by having 30 to 50 men handle it in relays; splice the cable in the 

 trench, and finally backfill the spoil and tamp it by hand. Later variations 

 of this method introduced one or more of the following units of machine 

 equipment: Power trenching machines: Caterpillar tractors with trailers 

 to straddle the trench, laying the cable directly from the reel into the trench; 

 Drag-line or other types of power backfillers; Power tampers or rollers. 



In order to further reduce the number of operations involved, speed up 

 the installation, and reduce the cost, large plow trains have recently been 

 developed which, except for splicing, in ordinary soil complete the job of 

 burying a cable in one pass over the route. The idea of plowing cable into 

 the ground is not new. In fact the great grandfather of all the cable plows 

 was designed by Ezra Cornell long before he established the university. 

 His "ponderous machine" drawn by a "long line of horses" was designed for 

 laying telegraph cable in the early 1840's, but the development was dropped 

 when the simple expedient of carrying wires on poles and insulators was 

 conceived. 



The large plow trains recently developed for installing telephone cable 

 are capable of burying either a single cable or a pair of cables together with 

 as many as three properly spaced lightning-protection wires, and of cutting 

 a slot for them as much as 50 inches deep where such a depth is required. 

 To provide the complete plow train has required the design of many pieces 

 of equipment which the word "plow" does not suggest to one's mind. The 

 plows and some of this equipment are discussed in this paper. 



A Frequency-Modulated Control-Track for Movietone Prints} J. G. 

 Frayne and F. P. Herrxfeld. A 5-mil frequency-modulated track 

 located between sound and picture areas is proposed to control reproduction 



1 Elec. Engg., Transactions Section, April 1942. 

 ^Joiir. S.M.P.E., February 1942. 



