Yes, John was aware of the issue of the 20 metre radius at Central when he
worked on the design, so it was improved to cope with that. They went
around those curves at a crawl though, not the 15 km/h or so that a
swivelling bogie tram can achieve on 20 metres radius. If there are plenty
of such curves on a system, each of these slow-downs cumulatively extend
the timetable. I note that the IWLR journey has now slipped back to 39
minutes since the Alstoms went onto the line and I doubt that anything will
change when the CAFs return after that structural stress experience. This
is a line on which a 30 minute journey is perfectly feasible with the right
trams and a good (Central European style) operation.
Tony P
On Saturday, 14 May 2022 at 11:23:38 UTC+10peterm...@... wrote:
> Hi Tony,
> Thanks to Jon Dunns efforts 2107 is good for 20M radius, and it has got
> around Cross street at the museum with no track issues since its wheels
> were half turned. Much better now on the corner with all wheels turned.
> Cross street is average 23m radius.
> Peter
> On Wednesday, 11 May 2022 at 13:24:56 UTC+10 TP wrote:
>
>> There is some confusion here about how long TfNSW was involved in IWLR.
>> TfNSW was basically a 2011 renaming of the former NSW Department of
>> Transport, so in that sense "TfNSW" (i.e. the same mob of people) was
>> around in the 1990s and should have plenty of experience to call on, if the
>> then bus-thinking dominated department had not kept the subject of light
>> rail at arm's length.
>>
>> It should be said also that the Variotrams, as fixed truck trams, were
>> unsuitable for IWLR too. Look at the catastrophic history of the Variotrams
>> purchased for Helsinki. It's just that John Dunn modified the design of the
>> Sydney ones to the extent that they could cope reasonably well, but they
>> contributed their share of "angle grinding" on the tracks over the years.
>> The Variotram design was selected because, at that time, there was no tram
>> with swivelling bogies AND 100% low floor on the market - so the design
>> was patched to make it a fair, but not perfect, choice for Sydney. Fully
>> low floor trams with swivelling bogies did not come onto the market until
>> after 2008, so there was plenty of opportunity for Alstom and CAF to say to
>> TfNSW "you need a swivelling bogie tram for this system" and neither of
>> them had a fully developed swivelling bogie model at the time, so they
>> would have lost the jobs if this became a sticking point. Fortunately for
>> them, TfNSW or its consultants did not know anything about the subject to
>> hold them to a standard and so we have what we have today.
>>
>> If you look at the specifications for modern fixed truck trams, somewhere
>> in the small print (unless the manufacturers' spin doctors have erased it
>> altogether) you'll see the caveat that these trams are suitable only for
>> systems with a minimum horizontal curve radius of 25 metres. The minimum
>> radius on the Central Station loop is 20 metres. Draw your own conclusions
>> as to which type of tram should have been purchased for Sydney.
>>
>> Tony P
>>
>> On Wednesday, 11 May 2022 at 10:41:30 UTC+10 jewiwa wrote:
>>
>>> Correction, David: TfNSW is expert in 'modern light rail'. Don't you
>>> dare use the dirty word 'tram' in its presence!
>>>
>>> JWW
>>> ------------------------------
>>> *From:*tramsdo...@... tramsdo...@...> on
>>> behalf of David McLoughlin mcloug...@...>
>>> *Sent:* Tuesday, 10 May 2022 11:13 PM
>>> *To:* TramsDownUnder tramsdo...@...>
>>> *Subject:* [TramsDownUnder] Re: Alstom Angle Grinder
>>>
>>>
>>> > The line opened in August 1997. Since then it's had one generation of
>>> Variotrams,
>>>
>>> I forgot to add, I recall reading in this group that the Varoiotrams
>>> were redesigned specially to cope with the profiles of that curve. If I
>>> recollect correctly, the tram operator was advised of the need for
>>> modifications and listened to the advice.... I recall the advice even came
>>> from members of this grouo.
>>>
>>> TfNSW was not involved in the establishment of that original line and
>>> only became the owner when Gladys (bless her) succeeded in making a start
>>> on the new George Street lines. It was thus unable to stuff it up from the
>>> beginning. I presume TfNSW had a similar contempt for that original line
>>> as it had/has for the George Street lines.
>>>
>>> David McL.
>>>
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>>