Okay, then...that explains it...thanks.
Lake Shore Limited and Train Length Issues
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Seaboard92
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I couldn't have explained it any better. In all regards I think it's a much more practical system because it allows for a system failure to be quickly rectified. Whereas on Amtrak's version one must be figuring out a solution immediately the Canadian version allows you to roll into a station, or terminal to fix the affected line.There are a lot of similarities with some significant differences.
Both the Amtrak and Canadian HEP systems use four sets of 4/0, 480V, three-phase cables through the train (train line). Both provide 1200kW HEP total capacity for the train. So the maximum load that can be supported by the Amtrak and the Canadian systems is the same.
The difference is in the way the power is distributed from the generator source(s) to the cars. Amtrak takes all four cables and ties them together at a junction point in each car. Electrically, the four cables act as one cable with four parallel paths. Since the four cables are connected, there can be only one generator as the source (barring the very difficult trick of frequency synchronizing two generators in two separate locomotives). Effectively, the Amtrak system is one generator, one circuit, and a failure anywhere in that circuit kills the entire system.
The Canadian system also uses the four 4/0 cables, but acting as four circuits. Each car is wired to use one of the four circuits, with the cars alternating from Train Line 1 (TL1) to 2, 3 and 4 to even the load distribution among the circuit. The cables run with two on the left side and two on the right side. Those pairs of cables can be sourced from separate generators (two locomotives) - one locomotive powering the two left-side circuits, and one the two right-side circuit. Since the left and right pairs are electrically separate, synchronizing the two generators is not required.
The Canadian system is set up for reliability. If a failure occurs on one side of the system (left or right), or with one of the two generators, automatic transfer switches connect the affected cars to the other side of the electrical system, and load shedding devices reduce the power load in each car to stay within the half system capacity. Despite the fault, train power stays on, although lighting, HVAC and other load will be reduced. With Amtrak, a fault must be cleared for the system to work.
So, basically, the two systems are physically similar and have the same capacity. However, a schematic diagrams of the Amtrak system would be one line from a single generator to all the cars, and the Canadian system would be four lines, two from each of two generators, and each car being fed from just one of the four lines, with the cars alternating the lines.
Clear (as mud)?
I think Newark has one of the longest platforms on the NEC but a good length isn't being used by Amtrak. It might be good for a good 18 cars. Jis or ThirdRail would probably have better information on that. I've seen a photo of the pre Amtrak Silver Meteor in the late 60s and its in the 20-30 car range.
Notwithstanding the layout or capacity of the cables for power distribution, different locomotives have different limits on the HEP they can provide. Providing HEP has a major impact on the available power for traction, unless a separate genset is in use (think F59-PHI).
Also, VIA HEP is 560V versus 480V for Amtrak, so the current (and voltage drop) is reduced by the same ratio, allowing for longer runs.
The Amtrak system (don't know about VIA) also has a continuity conductor which goes from the HEP source to the end loop on each side; if it breaks HEP is shut down.
The Amtrak system (don't know about VIA) also has a continuity conductor which goes from the HEP source to the end loop on each side; if it breaks HEP is shut down.
cpotisch
Engineer
Totally different route than the LSL. Irrelevant.
cpotisch
Engineer
If memory serves, one P42 can provide HEP to 18 Superliners. So it can definitely more than 18 single-levels.
jis
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800 kw, slice it and dice it as you see fit. Longer lengths increase voltage drop and line losses, new stuff like LED lighting saves. They were originally scoped for 16 SL assuming a 50kw average draw.
Mercifully, the 4/0 cable between railcars is fine strand flexible. For NY familiar folks, the very southern tip of Roosevelt Island is home to the FDR Four Freedoms Park. the runs from the monument end manhole to the panels are over 1000 feet, and it is 4/0 not so flexible.....just about smoked the super tugger....
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Though mostly low voltage draw, passengers are adding more and more, sleepers, coaches, or lounge.. though the push is to LED, the addition of plug ins maybe offsetting that some. What about that occasional hairdryer?
jis
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Not to mention the mini-Microwaves that people here are threatening to bring on board with a mini-Refrigerator attached.
cpotisch
Engineer
Is it possible that for extra long consists pushing the limits of HEP, Amtrak could configure the electrical systems in the cars to have a lower maximum output? In which case maybe passengers wouldn't be able to use a high power hairdryer or a microwave (which I have seen passengers use), but normal use wouldn't take a hit.
Ryan
Court Jester
How might they do that?
You have seen passengers use microwaves???
cpotisch
Engineer
Small ones but yes.
Alas, the theoretical and practical do not align. It is very common to limit the amount of current that can be drawn in a given circuit. Fuses and circuit breakers are the most common types of "over-current protection devices" Draw too much current, they trip or open. Chasing down tripped breakers enroute to allow an extra car that will almost be never needed, not likely. If you did a major rewire, there are a few other ways to segment the wiring that would allow better control of indivudual circuits, but again cha ching!
Actually, a decent sized microwave uses less power than a regular hairdryer.
I have seen Superliner sleeper outlets cut out under the load of a CRT television and VCR, so I'd guess anything much over 300W is verboten. So a very small microwave oven would probably work, but a toaster oven or blow dryer would be right out.
cpotisch
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I have had a few times when someone overloaded the circuit so a number of rooms were without power. Some of the older experienced SCA get to the breakers and fix the problem. Others prefer to wait for a maintenance person to fix it, which can mean a long time. I cautioned my daughters and granddaughters, all long hair, no hair dryers on the train. Amazingly they were creative, never complaining, never once using a hair dryer or curling iron or other heated hair appliance.
There are days when I've wished I had the guts to just shave my head. But although bald is now really cool for guys, the same isn't true for gals!Hair dryer? What hair dryer? You mean a towel? (see my avatar)....
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Have you seen a teen girls bag of "emergency equipment and products"? Then they have their necessities. After the "crane" (me) hoists the bag(s) up in to the car you start wondering about making the trip. My grandsons were easy, just their backpack for 10 days.Hair dryer? What hair dryer? You mean a towel? (see my avatar)....
Yeah, this is such a great candidate for Superliners but sadly we all know that isn't possible . . . although it actually could get pretty close to downtown Boston.
Could run it between Chicago and Albany and run low-level connector trains to NYP and BOS. I don't know if there are low level platforms left at recently rebuilt stations.
Could run it between Chicago and Albany and run low-level connector trains to NYP and BOS. I don't know if there are low level platforms left at recently rebuilt stations.
