STEEL VIADUCT REPLACING A TIMBER STRUCTURE. 985 
The girders were unloaded from trucks to cradles prepared for 
them, and each pair then connected with the cross and wind- 
bracing, and the sleepers fitted and bolted, each span then being 
ready for its place. 
The trestles were unloaded opposite their sites and slid over 
into place, and carefully levelled and lined up, bedded on the 
circular foundation blocks, usually four or five days before the 
girders were fixed, to give plenty of time for setting. 
Two travelling cranes were used on the siding for handling 
these. 
When the steel trestles were in place, and the new spans ready 
for erection, the old superstructure was removed, being first lifted 
with hydraulic ship-jacks and sliding rails lubricated with soft 
soap, and 1 + inch a shding-plates inserted, this being expedi- 
tiously done, as it took only a few minutes to lft with the 100 
ton ship-jack. 
iverything being ready to remove a section as soon as the last 
train had passed, the rails were removed and run back, the old 
girders having been sawn through with a diagonal cut, and the 
overhanging end supported by temporary props; and when the 
trap-bolts were removed, the jacks were manned, and the old 
superstructure slid over the ends of the headstocks and down 
sliding rails where the height was small, or arranged to turn over 
as it slid from the headstocks where the depth was sufficient, this 
operation taking from five to ten minutes. Meanwhile the engine 
attached to the crane had slung and brought over the new span, 
ready to lower into position ; and as soon as the first span was in 
position and bolted down, the rails were laid on it, and the opera- 
tion repeated until the gap was filled up. 
A tabulated account of each day’s work showed that No. 3 
viaduct of 4 spans (a total length of 118 feet) was erected on 
Sunday, July 4th, in about 5} hours; that 3 spans of No. 4 
viaduct (88 feet 6 inches) were erected on July 16th in 2? hours ; 
that on July 30th, 5 spans (147 feet 6 inches) were erected in 
2 hours 13 minutes; on August 13th, 5 spans in 2 hours 22 
minutes ; on August 20th, 5 spans in 2 hours 21 minutes; on 
August 27th, 6 spans (177 feet) in 3 hours 5 minutes; on 
September 4th, 5 spans in 2 hours 8 minutes; on September 
10th, 6 spans in 2 hours 37 minutes ; on September 17th, 6 
spans in 2 hours 35 minutes ; on September 24th, 6 spans in 2 
hours 37 minutes ; on October 8th, 6 spans in 3 hours 8 minutes ; 
on October 22nd, 6 spans in 3 hours; on October 29th, 6 spans 
in 3 hours; on November 26th, 5 spans in 3 hours; and on 
November 28th (Sunday), the closing span and fitting. 
The whole of the work was carried out without any delay to 
the traffic, and with no accident other than a few pinched fingers 
