kEiThZ
Superstar
I could see the province making them an offer they can't refuse.
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I could see the province making them an offer they can't refuse.
Amy Rose
Active Member
Flexity Freedoms with NOS?
leopetr
Active Member
For the curious, Flexity Freedom has a top speed of 80 km/h. I'm not sure how easy or hard this would be to upgrade.
nfitz
Superstar
What's the source for that? I was digging around, and all I could find was 70 km/hr for the Flexity Outlook, Flexity 2, Flexity Blackpool, etc.
Platform 27
Active Member
It's in the PDF brochure that's linked-to from the url leoptr provided
kEiThZ
Superstar
Who knows. But if Ottawa was offered them at the right price, maybe they'll put with the 80 kph top speed. Honestly, there's very few stretches in the plannned LRT where a 100 kph top speed would make a significant difference in travel time.
nfitz
Superstar
Oops ... so it is!
Looks like they are thinking Ottawa - the picture on page 15 of the brochure is in Ottawa, and shows a Flexity Freedom running through Major's Hill Park in front of the National Gallery. Might just be artistic though ... however there have been suggestions of building an LRT here to connect with Gatineau.
So what could they do to increase the top speed from 80 km/hr to 100 km/hr? I'd think it was doable ... isn't the spec for the CLRV and ALRV 110 km/hr?
reaperexpress
Senior Member
Yes, the CLRV can apparently go 110km/h but an ALRV cannot, because of its power-to-weight ratio.
In the case of an ALRV, upping the top speed would just require swapping the unpowered centre axles with powered ones.
I suspect that upgrading a Flexity would be harder, because the design is less inherently stable. On an ALRV, the centre bogie is attached directly to the articulation, controlling the car's motion. The Flexity, on the other hand, has floating sections which could move around more easily. That's fine around town, but might cause issues at highway speed. They would probably need to add motion dampers and such, as well as to increase the motor's power and/or gear ratio.
smallspy
Senior Member
It depends on whether the car design allows for the additional stresses of higher speed. Bombardier does make other LRTs capable of 100km/h and more, so they may have either not bothered with the Freedom design.
As for the current crop of streetcars in Toronto, all are limited to 80km/h. The CLRVs were designed with higher speeds in mind for operation on PROW, but it's unclear whether they were ever equipped to run at those speeds. They certainly haven't been while in service in Toronto.
Dan
Toronto, Ont.
EnviroTO
Senior Member
Most of the LRTs that get up to 100km/h are not low floor. With low floor LRT the wheels tend to be a smaller diameter meaning they must rotate more per distance traveled. Also higher speed LRTs tend to locate the trucks at or closer to the articulation point for greater stability.
smallspy
Senior Member
http://www.bombardier.com/en/transp...hicles/porto--portugal?docID=0901260d8000cbea
They exist. They may not be numerous, but they are out there.
Dan
Toronto, Ont.
EnviroTO
Senior Member
^ You are proving my point with that link. It isn't a 100% low floor LRT and the middle two trucks are located right next to the articulation point.
smallspy
Senior Member
Funny, you never mentioned that the cars had to be 100% to qualify by your rules. You asked for low floor, and those cars most definitely feature a low floor.
By the way, wheel size has no bearing on anything whatsoever. The gearing is one of the major the limiting features in calculating a top speed, as DC electric motors of that size don't like spinning at much more than 3000rpm.
Dan
Toronto, Ont.
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EnviroTO
Senior Member
If wheel size has no bearing then why do trains have such large wheels? Isn't it a waste of metal? I would disagree that wheel size has no bearing because it directly impacts surface friction, momentum, and ride. Also, placement of large wheels near the articulation point makes 100% low floor less possible. Any vehicle can support a low floor easily if you don't provide it throughout the vehicle since the hard part is always over the wheels.
smallspy
Senior Member
Sorry, let me be more specific - wheel size has no bearing on top speed whatsoever with modern trains using electric traction motors. Gearing is much more important - see my point above about DC motors.
Why do trains have such large wheels? I guess it depends on what you define as "large". Steam engines had large driving wheels because without gears the size of the wheel defined the top speed of the loco - that isn't the case when electric motors are used. You simply adjust the size of the gears.
What a large wheel does do however is give you a larger surface area with which to "grip" the rail. Most modern North American diesel freight locos use 44" or 45" wheels because of that, but yet they only run as fast as 65 or 70mph. Yet the UA TurboTrain, which did 170mph, had 24" wheels. The LRC coaches, which are designed for 130mph operation, use 28" wheels.
Dan
Toronto, Ont.