50 W. H. WARREN. 
required to take charge of loops on single lines, and in 
the saving effected by reducing the amount of detention 
to trains crossing one another at these crossing loops. A 
total expenditure of nearly £250,000 has been expended 
during recent years in duplication works. 
Strengthening Lines.—In order that the advantages of 
railway communication might be afforded to outlying dis- 
tricts, the Commissioners some years ago decided that it 
would be desirable to construct new lines in such districts 
in as cheap a manner as possible, strengthening them 
subsequently as the traffic developed. The Corowa line 
and the line between Molong and Forbes were origi- 
nally constructed as light ones with 60 fb. rails, on 
sleepers 8 feet by 9 inches by 43 inches, spaced about 
2 feet 10 inches centres, bedded upon 4 inches of broken 
stone ballast, and boxed up with the same material. 
The growth of traffic, owing to the opening up of the 
country for agriculture, necessitated the use of heavy 
engines for economical working, and it therefore became 
necessary to strengthen the permanent way by the provision 
of additional sleepers. This was done, and the sleepers 
re-spaced about 2 feet 2 inches centres, the result being 
most satisfactory; the lines, with the additional support, 
being rather more easily maintained than before, even with 
engines of the heaviest class working over them. 
Bridges.—When the first lines were constructed, loco- 
motives were much lighter than at the present time, and 
the iron bridges then erected were designed to give a 
sufficient factor of safety for the heaviest load that could 
be applied by engines then in use. The weight of engines 
having practically doubled, however, it was necessary 
some few years back to strengthen a number of the old 
iron bridges, notably those over the Wollondilly River on 
the main Southern line and over Solitary Creek on the 
