• Amtrak ACS-64 Sprinter Discussion

  • Discussion related to Amtrak also known as the National Railroad Passenger Corp.
Discussion related to Amtrak also known as the National Railroad Passenger Corp.

Moderators: GirlOnTheTrain, mtuandrew, Tadman

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  by STrRedWolf
 
Pensyfan19 wrote: Sun Mar 15, 2020 9:54 am
ApproachMedium wrote: Sat Mar 14, 2020 10:49 pm I call bs on the no results, the 4910 is always in service, i see it often and it seems like now there are at least 4 hhps in service every day. The last week i did not notice any acs-64s in marc service.
But just in case... (this was from another railroad.net discussion by the way) XD

http://www.hebners.net/Amtrak/amtACS/To ... arc618.jpg
Proposed livery for an ACS-64 based MARC engine. I did a quick search and found the same photo, but the engine was in New York Central livery.
  by Pensyfan19
 
STrRedWolf wrote: Sun Mar 15, 2020 6:01 pm
Pensyfan19 wrote: Sun Mar 15, 2020 9:54 am
ApproachMedium wrote: Sat Mar 14, 2020 10:49 pm I call bs on the no results, the 4910 is always in service, i see it often and it seems like now there are at least 4 hhps in service every day. The last week i did not notice any acs-64s in marc service.
But just in case... (this was from another railroad.net discussion by the way) XD

http://www.hebners.net/Amtrak/amtACS/To ... arc618.jpg
Proposed livery for an ACS-64 based MARC engine. I did a quick search and found the same photo, but the engine was in New York Central livery.
For more custom liveries for the ACS-64, including more for MARC, MBTA and more, please visit this link.

https://www.tomhirano.com/railroad/siem ... t-schemes/
  by CSRR573
 
B762732A-0AD5-4B68-A587-EC09311EEBB2.jpeg
Main transformer removal on ACS-64 625. Taken a couple of weeks ago with permission and full PPE
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  by ThirdRail7
 
gokeefe wrote: Thu Feb 20, 2020 9:20 pm
How much of a modification? Extra suspension or something else?
Complete redesign and replacement. The trackbed was likened to that of a third rail country.
  by twropr
 
In addition to #625 (see previous post), I have heard that #607 and #647 are having transformers replaced. Most of these motors are less than six years old. Did the AEM-7DCs or remans need to have transformer replacements this early in their lives? The E60s and HHP8s?
Andy
  by gokeefe
 
Makes me wonder if they've identified this as a "root cause" for certain issues ...
  by west point
 
These transformer failures make me wonder. How many hours have the motors had under 25 Hz CAT ? Could it be that when under 25 Hz that ventilation of the transformers is inadequate ? Has Siemens ever produced any motors that operated under 25 Hz CAT other than for Amtrak ?
  by DutchRailnut
 
thousands of locomotives that run on 16 2/3 hertz
  by west point
 
but is 16 2/3 transformer ventilation compared to 25 Hz scaled up ?
  by DutchRailnut
 
it would need even more cooling and would be bigger.
  by gokeefe
 
I would think voltage fluctuations and perhaps line noise might be more of a problem.
  by David Benton
 
west point wrote: Sat Apr 18, 2020 12:41 pm but is 16 2/3 transformer ventilation compared to 25 Hz scaled up ?
The lower the frequency (Hz), the bigger the iron core needs to be to maintain the magnetic field that transfers the "power" from one side of the transformer to the other. I'm not sure what effect it has on cooling, but doubt Siemens would miscalculate or not allow for the different Hz.
Third Rail mentioned rough track, maybe vibration is an issue.
  by gokeefe
 
I was thinking about that and wondering if perhaps rough track conditions create momentary surges in the electrical systems onboard.
  by hxa
 
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gokeefe wrote: Sat Apr 18, 2020 9:14 pm I was thinking about that and wondering if perhaps rough track conditions create momentary surges in the electrical systems onboard.
What may create additional surges are momentary loss of contact between contact wires and pantographs. But it doesn't seem to be a serious issue, as:
1. Amtrak engines are using one of the best pantographs in the world. Derived from Brecknell Willis's high speed pantograph, they are equipped with "aerofoils" which counteract the negative aerodynamic effects in high-speed operations, very simple in aerodynamic shape and are able to make swift changes in height.
2. The catenary used on former PRR lines is a somewhat "compound" catenary, consisted of a "contact wire", a "messenger wire" and an "auxiliary messenger wire". The contact wire, instead of being suspended by the auxiliary messenger wire, is clipped directly to the latter, so it is not a true compound catenary. Nevertheless, the presence of the auxiliary messenger wire makes the system very "elastic" and tolerant to vibrations. The section upgraded in the NJHSRIP program has true compound catenary, as well as tensioners that keep them in constant tensions now.
The drawback is the increased mass per unit length. The speed of transverse wave on a string is given by v=sqrt(T/l), where T is the tension and l the mass density. The larger the mass density, the slower the wave speed, and easier for trains to break the "sound barrier" on the catenary, a very dangerous situation never allowed to occur.
For this reason, compound catenarys are not used elsewhere after 1997, as HSRs built after that are aimed for true high-speed operations. As true high-speed operations would never occur in the near future on NEC, compound catenary is undoubtly the best option.
3. When the pantograph is off the contact wire, an arc forms in the gap. Arcs are natural current stabilizers, and are much more harmful to the pantograph themselves than the electric traction system.
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