Re: [NSW] Cityrail Millennium Train

["Geoff Lillico" <glillic@msn.com.au>]

Thank you. I think that sorts out the FACTS!

--
Geoff Lillico


"Al" <alpout@optusnet.com.au> wrote in message
3a973f67$0$25490$7f31c96c@news01.syd.optusnet.com.au">news:3a973f67$0$25490$7f31c96c@news01.syd.optusnet.com.au...
>
> Geoff Lillico <glillic@msn.com.au> wrote in message
> JApl6.1603$v5.5993@newsfeeds.bigpond.com">news:JApl6.1603$v5.5993@newsfeeds.bigpond.com...
> > Yes there are standards in place.
> >
> > I would hazard a guess and say that not one correspondant to this thread
is
> > a structural engineer and nor am I, but unless you have substantiated
> > evidence to the contrary, I believe it is unwise to suggest that these
new
> > trains do NOT comply to the standards set for the Bureau of Rail Safety
of
> > D.O.T. or those of the Australian Standards Authority.
> >
>
> You could be right there, but anyway it's not a structural engineer you're
> after, but a mechanical, which I'm starting my final year in on Monday, so
> here's my probably totally flawed thoughts about it.  Don't take it as
gospel,
> but rather as a guide to what the designers are considering.
>
> I also work for a company which makes fire trucks, and has done work for
> Goninan on train bodies, bogies etc.  Actually, half the people on the
floor
> there worked for Goninans when they were making the Tangaras and NRs, but
> that's another story.
>
> One thing to consider is that the trains could be built as a monocoque or
> unitary construction, similar to a passenger car such as a Commodore or
> Falcon.  They do not have a fixed chassis such as a truck, but rather the
load
> is taken by the panels all over the vehicle.  This could explain why it
looks
> flimsy, where it could actually have a very strong rigidity (essentially
one
> big box section).  Advantages to this are light weight and high strength,
> which is one reason why most passenger cars are made this way now.  It
also
> gives better energy absorption in a crash, which is why newer cars are
more
> survivable than older ones in crashes.
>
> Also, the material used can affect the standards.  Judging by the colour
of
> the metal in the photos, it's either aluminium or steel sheeting, probably
> aluminium, cause it can be made extremely strong but remains lightweight,
with
> a steel framework as a cheap, but effective backbone.  People, by and
large,
> aren't all that heavy (2000 people on an 8-car train ~ approx 180 - 200
tonnes
> to give a comparison to freight trains), so most of the structural
strength is
> required for the shock loadings that the trains experience, such as going
over
> gaps in the track at points, wind blast from passing trains at high speed,
and
> full throttle-full brake scenarios, such as an uphill into a station.
>
> Finally, the type of accident or load that you consider can make the shape
> substantially different to what you expect.  Passenger cars are designed
for
> accidents coming into the car from the plane of the road (ie front and
sides).
> What are the kinds of accidents a train can expect?  You could possibly
design
> the cab as a crumple zone, on the assumption the driver can get out in
time
> (re Glenbrook).  This also works both ways for front and rear end
collisions.
> You don't have to worry about T-bones, but rolling is another possibility,
> where you don't want the structure to collapse onto people inside it,
which is
> where a monocoque has another advantage.
>
> Hope that helps,
>
> Al
>
>