Acela II (Alstom Avelia Liberty): Design, Production, Delivery, Acceptance

Cant?

Cant (no apostrophe) is the difference in height between the low rail and high rail in a superelevated curve. Cant deficiency I believe is how far over the "balance speed" for a given cant is. So a train with a 4" cant deficiency, on a 7" cant track, is going at a speed that it would be perfectly balanced on an 11" cant. I'm sure our resident railroad folks can explain that better, and maybe correct me if I misspoke.

No, what I recall from what's been said here, CANT has been quoted as one of the problems with A2. I do sort of understand what CANT is. I do try to remind myself that while the cars can tilt to help passengers not feel the effect of curves, that locomotives do not, plus that the fact a car can tilt does not eliminate the issue of what a car can handle, CANT wise.

As I recall, there were also issues with the pantographs versus the rather ancient catenary that's not constant tension.

If the issues are because of the old PRR catenary then how does it fare on the areas where there’s constant tension wire? (Morrisville to New Brunswick)

Another friend who I haven’t seen in a while mentioned traction motor issues but I wouldn’t know anything about that if it was going on.

So, the train can't cant; Can't the pantograph cant into the Catenery?


If the locomotive is in "notch 3", you could say it was cantering...

MattW wrote: ↑Wed Mar 23, 2022 9:08 pm Cant (no apostrophe) is the difference in height between the low rail and high rail in a superelevated curve. Cant deficiency I believe is how far over the "balance speed" for a given cant is. So a train with a 4" cant deficiency, on a 7" cant track, is going at a speed that it would be perfectly balanced on an 11" cant. I'm sure our resident railroad folks can explain that better, and maybe correct me if I misspoke.

CANT, tilting cars, etc. is well explained with text, formulae and diagrams here: https://www.irjet.net/archives/V4/i12/IRJET-V4I1296.pdf

BandA wrote: ↑Thu Mar 24, 2022 11:42 am So, the train can't cant; Can't the pantograph cant into the Catenery?


If the locomotive is in "notch 3", you could say it was cantering...

Remember the Cant, Belters

Ken W2KB wrote: ↑Thu Mar 24, 2022 12:24 pm CANT, tilting cars, etc. is well explained with text, formulae and diagrams here: https://www.irjet.net/archives/V4/i12/IRJET-V4I1296.pdf

That's interesting and informative and it makes me wonder if a much simpler, cheaper, lighter, and far less maintenance pendulum system would be adequate on the NEC. The difference looks rather minor and the cost advantages over the life of the train would probably be huge. It just might make more sense. I just don't know how much the difference would be between the two in operational speed.

bostontrainguy wrote:

Ken W2KB wrote: ↑Thu Mar 24, 2022 12:24 pm CANT, tilting cars, etc. is well explained with text, formulae and diagrams here: https://www.irjet.net/archives/V4/i12/IRJET-V4I1296.pdf

That's interesting and informative and it makes me wonder if a much simpler, cheaper, lighter, and far less maintenance pendulum system would be adequate on the NEC. The difference looks rather minor and the cost advantages over the life of the train would probably be huge. It just might make more sense. I just don't know how much the difference would be between the two in operational speed.

Passive / pendulum tilting systems cannot tilt as far as active tilting systems, so they have speed restrictions the active tilting system won't have for the same trackage. Trains with passive pendulum tilting system have been used in the NEC before, but I don't know their schedules were. I think the Talgo trains in Washington state are limited to tilt only 3 degrees but are (if I understand correctly) designed for 5 degrees of tilt. It's entirely possible that most of the anticipated speed increases over the Acela I trains is based on a higher degree of tilt in the Acela II trains.

Instead of tilting the coach, tilt the passenger seats.

BandA wrote: ↑Fri Mar 25, 2022 7:32 am Instead of tilting the coach, tilt the passenger seats.

I can see it now. "OW! What the... Hey, who tilted this seat? I hit my head! Where's my lawyer?!?"

BandA wrote: ↑Fri Mar 25, 2022 7:32 am Instead of tilting the coach, tilt the passenger seats.

I was involved in the high-speed rail tests on the NEC in the eighties. We did several runs with various trains and part of that included being seated and standing during the tests. I actually experienced sharp ankle pain while standing and negotiating a curve at high speed in an Amfleet I. The entire car has to tilt for passenger comfort unless you want to strap everyone in like a rollercoaster and then you could really cut the travel time. Probably need Dramamine however.

I did try to find out some info comparing passive vs. active tilting and without serious investigation I quickly found some information. I found that passive tilting allows up to a 20% increase in speed on curves while active tilt allows up to 35% increase in speed.

Re: the catenary issues, last I heard the issue was pan bounce and that it had been effectively mitigated by running with only the rear pan and by outfitting said pan with spoilers (which create lift and keep the pan in contact with the wire).

Neat solution to that problem I must say!

mcgrath618 wrote: ↑Fri Mar 25, 2022 11:57 am Re: the catenary issues, last I heard the issue was pan bounce and that it had been effectively mitigated by running with only the rear pan and by outfitting said pan with spoilers (which create lift and keep the pan in contact with the wire).

vin diesel silly car franchise approved method