"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
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
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,