4 
DURABILITY. 
The durability of such a structure depends 
on the timber used. The oldest piece of timber 
that can safely be pointed to as having been on 
the ground for a long time is a piece of blood- 
wood now lying in Mr. Thos. Petrie’s paddock, 
North Pine River. About 1824, while the 
settlement was at Umpy Bong, a party in a 
boat went up the Pine River and landed, and 
began to cross cut the piece of timber referred 
to, and also chopped it with their axe. While 
doing so they were attacked by the blacks, and 
they then left. The limb is apparently sound ; 
the tree from which it fell is still growing. The 
mark of the axe is still distinct upon it, although 
the time is about 46 years ago. The next is a 
fence opposite my dwelling-house, put up in 
1842 or soon thereafter — that is 28 years ago. 
It stands, but is somewhat decayed. I may 
then safely say that a railway constructed of 
bloodwood, ironbark, or spotted gum will last 
thirty years, and that it may laBt sixty years. 
These I consider are our three most durable 
timbers ; bloodwood, however, cannot readily 
be sawn, it could only be used in log 
and hewn. Our next best timbers are 
blue gum, turpentine tree, black-butt, and 
stringy-bark. These are all that I at 
present know that I could recommend to be 
used in railway making, and the best are placed 
first. I have been spoken to about using our 
timber in the same way as they do in America 
in making wooden railways, — namely, by using 
good sized pieces of scantling for rails, cutting 
notches in cross-sleepers and fastening with a 
wedge. I am not going to say that it could not 
be done, but I do not look on it as being econo- 
mical. Our best timbers all spring in cutting, 
and to cut them straight they would require to 
be left so large as to allow their being cut twice, 
and it is a question if, even then, they would 
be straight. Logs can be cut to advantage as 
follows : — Cut up the middle with circular saw, 
then edged and cut straight on back. The 
centre placed downwards and the straight piece 
for rail. The next way is for larger timber — 
with two saws in frame take 10-ineh flitch out 
of centre, the slabs to be edged and straighted 
on back by circular saw. These would be unequal 
in thickness. The flitch to be cut up the middle 
to take the spring out of it, and cut into two or 
more pieces as it would allow. These pieces 
would be straight and equal in thickness. The 
central part of our timber ought always to be 
avoided, as it is there that it first begins to 
decay. 
BRIDGE. 
The model exhibited represents 80 ft. long 
and 8 ft. wide in the clear. The tie-beams and 
principal trusses are 12 inches wide, and 6 
inches deep. The king-posts are 12 x 8 and 
9x6. The braces or trusses are 6x6. The 
lateral triangular braces are 12 x 6. The lon- 
gitudinal sleepers are 12 x 8. The pathways 
are 12 x 3, and handrails with uprights not 
shown. The total quantity of timber in the 
* bridge is about 8000 feet. 
The whole work, including price of timber, 
iron work, and time of carpenters fitting pieces 
together, would cost here about £200 ; that is 
at the rate of £2 10s. per foot run. Circum- 
stances would determine in each case the foun- 
dations and abutments required. 
By published evidence I find that on the 
Main Range, near Fountain’s camp, the iron 
bridge which buckled, cost £18 per foot, and 
had it been of timber ic would have cost £14 
13s. per foot. Bridge No. 50, which is 80 feet 
long, cost £1280, or £16 per foot. Had it 
been of timber it would have cost £730, being 
more than 3^ times the probable cost of this 
one. I have not seen this bridge or design for 
a timber one, but cannot fail expressing an 
opinion that it is very like money being thrown 
away, and now we have to pay the interest 
thereof in increased taxation. 
The model and the weight 200 lbs., is far 
more than ever can possibly be put on to a 
train on a bridge the full size. Mr. Tiffin, 
Engineer of Roads and Bridges, has calculated 
the strain, and he states that it is capable of 
carrying six times that weight. Be that as it 
may, the present weight, 200 lbs., is ten times 
the greatest practicable moving load it can be 
subjected to. The new girder deflects about 
1-12 of an inch, and the old one considerably 
more, not being so well fitted. 
ESTIMATED COST OE RAILWAY, WITH HEWN LOGS 
AS SLEEPERS. 
One mile of railway equal to two miles longi- 
tudinal sleepers, and if sleepers 20 feet long 
would require 528 sleepers, and 528 cross- 
sleepers, 7 feet long. 
A pair of men will cross-cut and 
hew 12 sleepers, 20 feet long, in 
a day, or 44 days for the mile, 
at 16s. 
They could do the 528 cross-Bleepers 
in 26 days 
Drawing these to their places de- 
pending on circumstances — say 
Fastening together with 6 pegs to 
each cross-Bleeper, at 2d. per peg 
Wooden rails 2 x 2=10,560 1. ft.= 
3520 feet, at 20s. 
Pegging rails to sleepers, at average 
of 1 to 2 feet=5280, at Id. 
Earthwork, digging holes for cross- 
sleepers and ditch, or ditches to 
drain ground — say 
Bridges — say per mile on average 
£35 
4 
0 
20 
16 
0 
40 
0 
0 
27 
0 
0 
35 
4 
0 
22 
0 
0 
200 
0 
0 
200 
0 
0 
£580 
4 
0 
200 
0 
0 
£780 
4 
0 
£300 
0 
0 
If with iron rails, 20 lbs. per yard, 
extra 
Thereby making road for horses at £1080, and 
for engines at £880 per mile. 
SAWN TIMBER. 
Using sawn timber, 10 x 3, instead of hewn 
logs for longitudinal and cross sleepers, would 
require other £200. 
Printed at the COURIER General Machine Printing Office, George-street, Brisbane. 
