Take a look at theTramlink tracks near Church Street tram stop at this
Google Streetview link: http://goo.gl/maps/3w0p7

What is the advatage of having the point so far from the curve?

--
jhk

On Monday, December 16, 2013 5:13:51 PM UTC, Jarle Hammen Knudsen wrote:
Take a look at theTramlink tracks near Church Street tram stop at this
Google Streetview link: http://goo.gl/maps/3w0p7
What is the advatage of having the point so far from the curve?


One possibility is to place the point in a convenient place compared to the associated gubbins (control/power supply, for example; see the cabinets next to the point end. It may be that the cabinets were only allowed there and not elsewhere).

Another possibility is that there is scope to change the alignment of one track relative to the other more than if a more conventional point end is used.

Both or neither may be the actual case for this location!

PhilD

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On 16/12/2013 17:13, Jarle Hammen Knudsen wrote:
Take a look at theTramlink tracks near Church Street tram stop at this
Google Streetview link: http://goo.gl/maps/3w0p7

What is the advatage of having the point so far from the curve?

IIRC it keeps the moving parts out of the way of road traffic. It maybe
also has some signalling benefit, but I've forgotten what if anything
that is.

If you really want to know you could try the Tramlink e-mail group on Yahoo.
--
Arthur Figgis Surrey, UK

On 2013\12\16 18:59, Arthur Figgis wrote:
On 16/12/2013 17:13, Jarle Hammen Knudsen wrote:
Take a look at theTramlink tracks near Church Street tram stop at this
Google Streetview link: http://goo.gl/maps/3w0p7

What is the advatage of having the point so far from the curve?

IIRC it keeps the moving parts out of the way of road traffic.

I was told by workmen working on these points that this is the reason,
although there is no particular reason why workmen should know the true
or complete answer.


It maybe
also has some signalling benefit, but I've forgotten what if anything
that is.

In Amsterdam the diverging junctions can have enough room for three
trams or more between the points and the road junction where the routes
geographically diverge. This is done so that multiple trams can arrive
gradually during a red phase and each be put on the correct track, and
then when the light turns green they can all whoosh off quickly in their
various directions. If the points were at the junction, there would be a
wait between the trams traversing the junction while the points were
changed, lengthening the green phase and reducing the capacity of the
junction. But I don't think that is an issue at the Croydon junction
concerned.

On 16/12/2013 19:49, Basil Jet wrote:
On 2013\12\16 18:59, Arthur Figgis wrote:
On 16/12/2013 17:13, Jarle Hammen Knudsen wrote:
Take a look at theTramlink tracks near Church Street tram stop at this
Google Streetview link: http://goo.gl/maps/3w0p7

What is the advatage of having the point so far from the curve?

IIRC it keeps the moving parts out of the way of road traffic.

I was told by workmen working on these points that this is the reason,
although there is no particular reason why workmen should know the true
or complete answer.


It maybe
also has some signalling benefit, but I've forgotten what if anything
that is.

In Amsterdam the diverging junctions can have enough room for three
trams or more between the points and the road junction where the routes
geographically diverge. This is done so that multiple trams can arrive
gradually during a red phase and each be put on the correct track, and
then when the light turns green they can all whoosh off quickly in their
various directions. If the points were at the junction, there would be a
wait between the trams traversing the junction while the points were
changed, lengthening the green phase and reducing the capacity of the
junction. But I don't think that is an issue at the Croydon junction
concerned.

I've seen it suggested that allowing more than one UK (or Croydon?) tram
through a set of lights per cycle is Not Allowed, as it would cause the
sky to fall in, or something.

--
Arthur Figgis Surrey, UK

In message , Jarle Hammen
Knudsen wrote:
Take a look at theTramlink tracks near Church Street tram stop at this
Google Streetview link: http://goo.gl/maps/3w0p7

What is the advatage of having the point so far from the curve?

If the pointwork was at the divergence, trams could be held blocking
Church Street waiting for them to move. If the points failed, that
blockage could be there a long time. Putting it back where it is means
they don't hold anything up.

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
Please reply to the Reply-To address, which is:

Arthur Figgis wrote in
o.uk:

On 16/12/2013 17:13, Jarle Hammen Knudsen wrote:
Take a look at theTramlink tracks near Church Street tram stop at
this Google Streetview link: http://goo.gl/maps/3w0p7

What is the advatage of having the point so far from the curve?

IIRC it keeps the moving parts out of the way of road traffic. It
maybe also has some signalling benefit, but I've forgotten what if
anything that is.

You may be right, but in that location it looks like the diverge point is
on a trams-only bit of road.

There is a cross street beween the points and the diverge point. If a tram
got to the diverge point and had to stop because the points were set the
wrong way, then it looks like it would block the cross street. Maybe
that's a factor. Or not.

Peter

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|| Peter CS ~ Epsom ~ UK | pjcs02 [at] gmail.com |