Re: Wellington N.S.W rail bridge

[Bruce Greening <norrail@optusnet.com.au>]

"f.u.i.t.b.e.t" wrote:

> Is not the one at Wagga the same design too?
> It has many many fractures and because of the brittle nature of the iron

Evidently the cast iron in the Wagga bridge is better quality. When the bridges
were built (There are a number around NSW to the same design) different
foundries in the UK manufactured the iron, with varying quality, hence while the
designs are similar, the capacity of the bridges may vary.

The bridge at Wagga has had many more loads (cyclic repatriations causing
fatigue) than the others, but it was also altered in the 1930's I believe, when
the portals were moved to different locations, and constructed in steel. The
Wagga bridge has had a speed restriction for many years, due to fatigue cracks
in the cross girders. Currently neoprene pads are being inserted between
members, and strain gauging is being carried out to asses the results, with a
possible lifting of the speed.

>
> >
> "Bruce Greening" <norrail@optusnet.com.au> wrote in message
> news:3ABF03BF.D4C8070@optusnet.com.au...
> > The reason for the current restrictions is deformation in one of the
> arches has
> > been observed. New arches are being constructed and will be fitted in a
> few
> > weeks time. Meantime extensive checks on the design and strength of the
> bridge
> > are being carried out. Obviously new computer aided design tools allow
> much more
> > detailed checking than would be available to original designers.
> >
> > Ian Larcher wrote:
> >
> > > If memory serves me correctly the reason for the 10kph speed limit on
> the
> > > Wellington Bridge is its Wrought Iron (not steel) construction, like
> several
> > > other bridges of its era (Bathurst for one)  it apparently was designed
> &
> > > constructed in the UK then dismantled shipped out here & reassembled.
> > >
> > > As far as I am aware the only bridge of this design not to have a speed
> > > restriction is that at Cowra, the last of this design built. It was
> > > constructed in Belgium of Steel, but still retains the cast iron piers
> > > common to all this design. I was always told that the speed restrictions
> > > were because of the brittleness of wrought iron compared to steel.
> > >
> > > "William Ivery" <willivery@optusnet.com.au> wrote in message
> > > news:3abc8d39$0$25519$7f31c96c@news01.syd.optusnet.com.au...
> > > > If the bridge was closed the XPT would terminate at Orange and
> passengers
> > > > transfered to Stuart Town, Wellington and Dubbo by road.
> > > >
> > > > The bridge itself is alright (its made of steel), the problem is that
> the
> > > > track is on wooden sleepers and there are white ants in them, hence
> the
> > > > speed restriction and dirversion of freight trains because they are
> too
> > > > heavy for the damaged sleepers.
> > > >
> > > > William Ivery
> > > >
> > > > "Chris Brownbill" <cbrnbill@enternet.com.au> wrote in message
> > > > news:3ABC47DD.CDC83F8A@enternet.com.au...
> > > > > Tom & Maria Jessop wrote:
> > > > >
> > > > > > it is also believed that XPT W27/28 also went via Parkes to Dubbo
> on
> > > > > > Thursday 22/03/01.
> > > > >
> > > > > I find that hard to believe.  Surely it would never get there and
> back
> > > in
> > > > anything like the time available to make a day return to Sydney.
> > > >
> > > >
> >
> > --
> > Bruce L. Greening
> >
> > Norrail@optusnet.com.au
> > http://members.optusnet.com.au/~norrail
> >
> >

--
Bruce L. Greening

Norrail@optusnet.com.au
http://members.optusnet.com.au/~norrail