RE: Re: Sydney Tram - CAF
prescottt
Tuesday, September 17, 2013 8:59 PM
That Nantes tram has too much front overhang - a giant lever!
The inner west line in Sydney has a snake-like winding profile, very little straight track. Although the curve radius is in theory OK for a fixed truck tram, when they are operated at speed they are producing considerable lateral forces. I feel the yawing in the Variotrams in certain places and they don't have so much overhang. It will be interesting to see how the CAFs perform.
I understand that the line has some premature track wear and the originally much-vaunted 80 km/h maximum speed has been brought down to preserve the track. There are (or were last time I travelled) much lower speed limit boards in the section where the yawing is worst, so they must be aware of the issue. Yet they go and buy more fixed bogie trams with an even bigger front overhang!
The same lack of intelligence seems to have driven the door decision. I have been having big arguments here about the importance of sufficient doors, but there is a strong emphasis on maximising seating. But nobody here recognises that if you want to maximise seating you need unidirectional trams (apart from their other advantages previously discussed).
Ironically, the second-hand CAFs acquired for the line from Velez-Malaga have a more decent number of doors - 4 + 2 single (equivalent of 5) - which makes the decision on the new-builds look even more stupid. I await what sort of design disaster will be chosen the the 45 metre CSELR trams. At least on Gold Coast they have something more sensible - 6 doors and 2 singles, equivalent to 7 in 45 metres. And they get 80 seats in that, which I think is quite decent.
By the way, I note that CAF is claiming passenger capacities over 300 for the inner west trams. They must be using 8ppsm which is way too theoretical. The operator rates the Variotrams at 220.
cheers
Tony P
--- In [email protected], <[email protected]> wrote:
> > Why only a single door in modules 2 & 4 and not two doubles each?The Urbos for Nantes (36m) does have a double door at the front end:
> Because of the layout of the tram, they can't get a double door ahead
> of the end bogie like they did on the Variotram. The overhang/swept
> path would be too great. Common now on these multiarticulateds. The
> Variotram was a bit unique.
http://tinyurl.com/kbetzhb
Obviously, with the "two rooms and bath" (multiarticulated)
configuration, the huge front overhang (=>mass moment of inertia) will
significantly worsen the problem of track wearout due to excessive
lateral forces on the track. And it won't help with yawing either.
Bombardier's first "Outlook" (they called it "Cityrunner" back then)
for Graz also had double front doors.
> I guess they figured 4 doors ( 2 and 2 halves) is enough for theThe equivalent of three double doors for a streetcar that's 33m in
> relatively low use of the inner west line.
length would probably set a new world record.
Over here three double doors for a 28m car are already hopelessly
insufficient during peak hours. They would need five to handle the
passengers with decent dwell times.
The new cars for Munich have eight double doors for 36m length,
those for Braunschweig have six double doors, which would be the
minimum for that length imho.
Sincerely,
Wolfgang
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