— 222 — 
FOR RAISING DOUBLE TRACK BRIDGES 
SPAN 
No. OF MEN REQUIRED 
Plate Girders 
From 15 to 20 
Pony Trusses 
，ノ 25 5 〇 
Tliro. Spans under 10 (V 
，， ’ 3 〇 ” 4 。 
10 0， to 125 ， 
,， 4 〇 ，， 45 
125 ， ，， 150, 
，， 45 « 55 
150’ ，， W 
，， 55 ，• 6 〇 
175 ， ” 20 o' 
•• 〇〇 „ 7 ° 
20 Of „ 225' 
，， 7 〇 ，. 8 〇 
225’ ，， 250 ， 
>» 2 〇 yy Q 5 
250 ， ，， 275 ， 
，， 95 115 
275 , ” 
，， 115 ,， 135 
If the bridge is to be erected rapidly the number given in the table can be pro- 
bably advantageously increased by from twenty-five to fifty per cent. 
The cost of raising a bridge depends more upon the foreman than upon thö 
men. The best men will fail to do their full quota of work it* tbo foreman be not 
energetic. Nor does it suffice to have simply a good worker for a foreman : he must 
know how to keep the gang busy, or they will stand by and look ou, while he does 
tlie work. Ho should also have their good will, or the progress of the work will bß 
unsatisfactory. 
