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

hxa wrote: ↑Sun Nov 07, 2021 7:52 am Just found an FRA report on the exact same issue:

https://railroads.dot.gov/sites/fra.dot ... INTERC.PDF

Apparantly Siemens's ICE trainset was successfully tested for EMI on the corridor. The test covered scenarios from max traction to max braking and from zero to line speeds, with a specific focus on cab signal interference. Siemens did reduce the 100 Hz harmonics by an active filter in addition to a vital protection circuit which would fail-safely cut off the MCB once 100 Hz current went above 1 amp. Theoretically Alstom could take similar or better approaches to this problem.

Interesting, but proprietary testing and design by Siemens, not Alstom. Maybe Amtrak should have bought Siemens HSR trainsets so as to not have to redesign the circuitry over again. But now Alstom must do it again, or pay Siemens a small fortune to license it.
Is asking General Motor by Ford or vice versa to use their copyrighted designs common? No, I did not think so. Never-the-less, we know there is an engineering solution that could solve this problem. Will Alstom be able to figure it out on their own?

The Silverliner V’s needed a similar filter to be applied, IIRC.

electricron wrote: ↑Sun Nov 07, 2021 9:19 am

hxa wrote: ↑Sun Nov 07, 2021 7:52 am Just found an FRA report on the exact same issue:

https://railroads.dot.gov/sites/fra.dot ... INTERC.PDF

Apparantly Siemens's ICE trainset was successfully tested for EMI on the corridor. The test covered scenarios from max traction to max braking and from zero to line speeds, with a specific focus on cab signal interference. Siemens did reduce the 100 Hz harmonics by an active filter in addition to a vital protection circuit which would fail-safely cut off the MCB once 100 Hz current went above 1 amp. Theoretically Alstom could take similar or better approaches to this problem.

Interesting, but proprietary testing and design by Siemens, not Alstom. Maybe Amtrak should have bought Siemens HSR trainsets so as to not have to redesign the circuitry over again. But now Alstom must do it again, or pay Siemens a small fortune to license it.
Is asking General Motor by Ford or vice versa to use their copyrighted designs common? No, I did not think so. Never-the-less, we know there is an engineering solution that could solve this problem. Will Alstom be able to figure it out on their own?

Its a common problem , and a relatively simple fix . Most modern signaling systems probably don't use such a low freguwncy , so alstom may not have struck it in Europe.

Interesting question; Germany, Austria, Switzerland, and Sweden had 16 2/3 Hz (I believe now 16.7 to avoid harmonics issues), but I don't know whether any Alstom equipment is in service on those systems. I was told by a signal engineer that the PRR once tried three E44's at the head of a coal train and the harmonics of the 25 Hz return current wiped out the cab signals, resulting in widespread Restricting indications.

Maybe there is no problem from Gate to BOS with 60 Hz CAT? Wonder how the EMI was mitigated with the conversion of MNRR from 25 to 60 Hz ? Maybe was studied at TTC with the conversions to 60 Hz by MNRR and NJT ? Japan might have transferrer information ? Only location that used 60 Hz at that time with it also using 60 Hz and all Europe not 60 Hz. There was no CAT in USA on signaled RRs with any 60 Hz during the study year. The few short electric coal haulers did not have signaling ?

I would think a migration to higher Hz for signal/communication will gradually happen anyway. 50Hz is 25 bits of info per second(assuming they need at least a on and off for a bit), as they want / need to pass more information through a wire / track.

west point wrote: ↑Tue Nov 09, 2021 10:35 am Maybe there is no problem from Gate to BOS with 60 Hz CAT? Wonder how the EMI was mitigated with the conversion of MNRR from 25 to 60 Hz ? Maybe was studied at TTC with the conversions to 60 Hz by MNRR and NJT ? Japan might have transferrer information ? Only location that used 60 Hz at that time with it also using 60 Hz and all Europe not 60 Hz. There was no CAT in USA on signaled RRs with any 60 Hz during the study year. The few short electric coal haulers did not have signaling ?

Well, 100Hz is the 4th harmonic of the original 25Hz frequency, hence the interference. 100Hz is not a harmonic of 60Hz. When they changed to 60Hz, they actually eliminated a major source of interference, rather than created a new one.

David Benton wrote: ↑Tue Nov 09, 2021 2:14 pm I would think a migration to higher Hz for signal/communication will gradually happen anyway. 50Hz is 25 bits of info per second(assuming they need at least a on and off for a bit), as they want / need to pass more information through a wire / track.

But here's another thing: the running rails are inductive, the higher the frequency the shorter the transmission. For transit operation, audio frequency track circuits are perfectly fine, as what they need is short headways at low speeds (thus short signal blocks). But for mainline operation, conversion to AFTCs has pros and cons. On one hand, they eliminate most insulated joints and are more robust against low order power harmonincs. On the other hand, they are constrained in length. The French came up with an idea that the inductance of running rails may be compensated by capacitors connect to the rails every several hundred meters. Even with these compensation capacitors, an AFTC block rarely exceed a mile. Moreover, if slab tracks are used, the distance can be halved due to the inductance of beam-loops within these slabs.

https://www.youtube.com/watch?v=MYpx8M_hnuw

A few livery differences I noticed with trainset 3. The cafe car door now blends, they flipped the Acela logos on one of the power cars so they now always face forward, they added (or lowered?) a reflective strip along the train, and the biggest change was the addition of numbers to each car.

I still wonder if they made any changes to the horn, but I guess time will tell. The body mismatch will always look goofy to me, but it's good to see it closer to the end product.

Hell, what is with the red doors in first class? Didn't they strip off the protective vinyl off of them before installing them?

Red for first class to give it a distinguishing color/quickly ID the door. European trains also color code the doors by class.

I want to paint it black

Just bring back Penn Central or give the train to Norfolk Southern and they'll paint the whole set black.

Give it to NS and they'll try to put an SD60E on the front.

Why not just a big "F" on the door(s) ? Just like the 1 and 2 on European trains.