Thinking back on your remarks re squeal on curves ..... remember the bloke
who walked around the city with his bucket of grease and his stick with a
piece of hessian on it greasing the rails on the curves and points also.
Ellis
From:TramsDownUnder@... [mailto:[email protected]]
On Behalf Of Dudley Horscroft
Sent: Sunday, 16 June 2013 6:18 PM
To:TramsDownUnder@...
Subject: Re: [TramsDownUnder] GCLR Surfers Paradise Blvde 2 11.6.13
"I also wonder whether there is any superelevation on these curves not
intersected by cross streets. I believe superelevation helps trams around
curves as the vehicle tends to fall towards the inside of the curve, thus
greatly reducing wear on the outer rail, and wheel flanges as well. I
believe the reason some curves in Melbourne squeal and others don't are
related to superelevation, or lack thereof."
If there is any superelevation it is likely to be very small. Even so, the
trams should always go round the curves faster than the speed at which the
centripetal force tending to move the tram out balances the force down the
slope tending to slide it towards the centre of the curve. This is because
- usually - tram wheels are coned to give good centring on the straights.
When a set of wheels is coned, the wheelset on its own would follow a
slightly sinuous curve along the line. This, providing the track is good
and the coning is right, prevents the flange coming into contact with the
rail head. This means wear is greatly reduced.
When the coned wheelset meets a curve, it should shift outwards, so that the
outer wheel is running on a section of the tyre slightly greater in diameter
than the inner wheel is rolling on. This assists in curving, reduces wear
and reduces noise. Squeal will probably be worst when a coned wheel is
running around a superelevated curve at a speed below the equi- something -
forget the word for it for the mo - speed, so that the inner wheel has the
higher diameter and the outer wheel the smaller - result high squeal and
high wear. Not Good!
In Sydney the new trams used to squeal horribly when rounding - very slowly
- the top of the ramp into the Colonnade at Central. Later I noticed that
they came round faster and squeal was reduced. I believe that the track may
have been lubricated here to help - but am not certain on that.
Regards
Dudley Horscroft
----- Original Message -----
From: Richard YOUL mailto:[email protected]
To:TramsDownUnder@...
Sent: Wednesday, June 12, 2013 9:14 AM
Subject: Re: [TramsDownUnder] GCLR Surfers Paradise Blvde 2 11.6.13
I quite agree with your construction method comments.
In view of the close association GoldlinQ apparently has with Melbourne, I
don't know why the same method was not used up here.
I did not know about the noise reduction provided by the Fill and Bitumen
method used in Melbourne, but that advantage aside, I think the system of
setting half-sleepers in a concrete base is ideal, and on curves just goes
back to what Brisbane always did - set curves in bitumen even when adjacent
track was concreted.
The attached photo was taken by Tim Boxsell with my camera during his visit
on 25.3.13. The view is from the Q1 building in Surfers Paradise and looks
down on the Gold Coast Highway as it threads its way south. The haphazard
way how isolated sections of track are close to each other is also very
clear. In this case it appears as though the tracks are separating for the
insertion of an island platform.
Unless the tramcars are very gentle on curved track, it won't be too long
before track replacers are cursing the use of all that steel in the
construction.
I also wonder whether there is any superelevation on these curves not
intersected by cross streets. I believe superelevation helps trams around
curves as the vehicle tends to fall towards the inside of the curve, thus
greatly reducing wear on the outer rail, and wheel flanges as well. I
believe the reason some curves in Melbourne squeal and others don't are
related to superelevation, or lack thereof.
This photo may help Tony Prescott and others understand that 70km/h speeds
will not be possible on certain sections of the tramway, and in fact the
view I took yesterday in the centre of Surfers Paradise (thanks for your
compliment, Geoffrey) will result in that section of track having a quite
low speed limit, party for curves and partly for distracted meandering
pedestrians many of whom will never have seen a tram before and will expect
it to weave around them.
Regards,
On 11/06/2013, at 10:38 PM, Andrew C wrote:
What a great thing the new light rail will be. It is a pity that it wasn't
constructed like Melbourne's replacement tracks, with a bitumen surface,
which is much quieter and looks better. Still, quite a momentous project and
watch the naysayers go silent as passenger numbers exceed forecasts.
Andrew C.
From: Richard YOUL mailto:[email protected]
Sent: Tuesday, June 11, 2013 8:11 PM
To:TramsDownUnder@...
Subject: [TramsDownUnder] GCLR Surfers Paradise Blvde 2 11.6.13
This view is taken a little further south, again looking south.
It is quite possible that the central street lights are not connected yet,
as the temporary ones attached to very large concrete blocks are still in
place. One of these is visible in the distance, and clearly visible in the
previous view, protected by some portable fencing.
It is not too hard to imagine a tram coming around the bend in the distance.
Regards,