XC. PERCY ALLAN. 
LIFT BRIDGE OVER THE MURRAY AT SWAN HILL 
By Percy ALLAN, Assoc, M. Inst. C.E., Assoc, M. Am. Soc. C.E. 
[With Plates 1- 4.] 
[Read before the Engineering Section of the Royal Society of N. 8. Wales, 
November 18, 1896. ] 
Tue Lift Bridge over the Murray River at Swan Hill having 
just been completed, and the author having in 1894, under Mr. 
Hickson, m. Inst. c.Z,, then Engineer-in-Chief for Public Works for 
New South Wales, designed the structure, has the honour of 
placing before the members of the Section a description of es 
work—before entering on the subject of the paper, it seems desir- 
able to briefly refer to the character of the river traffic to be 
provided for, and the considerations leading to the adoption of 
lift bridges—whilst a short resumé of the lift bridges previously 
erected in the Colony, may be of interest. 
The report by Mr. Darley, m. tnst.c.z., Engineer-in-Chief for 
Harbours and Rivers in 1890, on the Locking of the Darling, 
conveys an idea of the large traflic using the great rivers of the 
Colony, the number of steamers and barges trading on the Darling 
and Murray Rivers being given as two hundred and twenty-two 
with a total net tonnage of 20,358. The traffic consists mostly 
of steamer with barge in tow carrying in some cases 1,000 bales 
of wool. The largest steamer of which the author has a record 
is 123’ long, carrying a width of 33’ 6” over sponsoons, and 
requiring a minimum headway of 28’ when flying light, this 
vessel trading between Swan Hill and Mildura on the Murray 
River. 
The considerations leading to the adoption of lift bridges for 
the Darling, Murray and Murrumbidgee Rivers my be summari 
thus :-— - a 
1. Economy. 
