THE PANAMA CANAL 



177 



from 25 to 35 steel side dumps to a train. 

 The available dump grounds in the vi- 

 cinity of the cut were utilized to their 

 fullest capacity by the French and dur- 

 ing the earlier periods of American con- 

 trol, so that longer hauls are necessary. 



The new line of the Panama Railroad, 

 being above the lake level, requires many 

 heavy embankments, which offer suitable 

 places for depositing material. The 

 breakwater from Balboa to Naos Island 

 offers a dump, though requiring an aver- 

 age haul of 11 miles. 



As difficulty is experienced in extend- 

 ing this breakwater, additional dump 

 tracks are provided at Balboa, so as not 

 to delay the trains, and land at the inner 

 end of the breakwater is being reclaimed ; 

 already 253 acres have been filled in. 

 The interior swamps in the vicinity of 

 Ancon are also to be filled. From 16 to 

 22 trains of material are sent daily to 

 Gatun, an average haul of 25 miles, and 

 used in building up the toes of the dam 

 or for large rock to place in the concrete. 

 The remainder of the excavated material 

 is wasted on extensive dumps at Mira- 

 flores. A large dump ground at Taber- 

 nilla was used, but is abandoned for the 

 present. 



The Lidgerwood flats are dumped at 

 Miraflores, Balboa, and on the relocated 

 line of the Panama Railroad, where 

 special equipment is kept to handle them, 

 consisting of plows, unloaders, spreaders, 

 and track-shifters. The plow is attached 

 to one end of the train, and the unloader, 

 consisting of a steam-driven drum on 

 which is wound the cable, at the other 

 end. To stretch the cable, the train 

 passes between two uprights to which 

 the cable is attached temporarily, and by 

 moving the train the cable is drawn from 

 the drum to the plow to which the end 

 of the cable is attached. Winding the 

 cable on the drum draws the plow the 

 length of the train, removing the load. 



After the material is plowed off, the 

 spreader performs its functions, and, 

 when no longer capable of throwing the 

 material beyond the edge of the dump, 

 the track is shifted by a device patented 

 by W. G. Bierd, formerly general man- 



ager of the Panama Railroad, which 

 raises by one motion the track with the 

 ties so as to clear the ground, and by 

 another motion pulls it sidewise. The 

 usual throw is two and a half to three 

 feet, though, if the rails will permit, the 

 track can be thrown as much as nine 

 feet in one throw (see page 179). 



The steel dump-cars require no special 

 or extra appliance for their operation, 

 and can be dumped as easily on curved 

 as on straight track. They also dump 

 to either side. 



Work has been in progress on the Cu- 

 lebra Cut since 1880, and during the 

 French control 18,646,000 cubic yards 

 were removed. Between Gatun and Bas 

 Obispo, the northern end of Culebra 

 Cut, the French excavation which is use- 

 ful to the present project amounted to 

 2,201,000 cubic yards, or a total in the 

 Central Division of over 20,000,000 cubic 

 yards. The total estimated amount of 

 material to be excavated from May 4, 

 1904, in this division was 97,125,018 

 cubic yards, of which, up to January 1, 

 191 1, 67,792,855 cubic yards have been 

 removed, or 69.7 per cent. It is expected 

 that all the excavation in the lake section 

 will be finished by July 1, 191 1. 



Some idea of the magnitude of the 

 operations may be formed from the fact 

 that this division has within its jurisdic- 

 tion over 200 miles of 5-foot-gauge track 

 laid, about 55 miles of which are within 

 the side slopes of the Culebra Cut alone. 



the: great dam at gatun is a veritable 



hill 



An earth dam across the Chagres at 

 Gatun impounds the water of the river 

 and creates the lake which constitutes 

 the summit level. The dam is 7,500 feet 

 long over all, measured along the top, 

 and, according to the latest profile, it is 

 2,100 feet wide at the base, 398 feet 

 through at the water surface, reference 

 85, and 100 feet wide at the top, which 

 is 115 feet above sea-level. It crosses 

 two valleys separated by a hill rising to 

 elevation no, in which the regulating 

 works are being constructed. Of the 

 total length of the dam, only 500 feet 



