# P42DC vs Charger



## CSXfoamer1997 (Jan 26, 2016)

Which of the two do you think could do the job better with a Long-Distance train, whether it's Viewliners or Superliners?

Two P42DC's or one Charger?


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## CCC1007 (Jan 26, 2016)

This question is moot at this time, as chargers have yet to be built.

That being said, there are many reasons that one or two locomotives is preferred on certain routes.


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## west point (Jan 26, 2016)

Comparison is very bad.

1. Both P-42s and Sprinters have approximately same HP.

2. So any train needing 2 or in the case of the Builder into snow 3 locos would be same for either loco.

3. That said AC traction motors have better tractive effort at higher speeds and can run in a range of speeds better.

4. DC traction motors ingest fine snow and short out many times where as AC very seldom. Note how well ACS-64s operated in the just past snow storm using AC traction motors.


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## PerRock (Jan 26, 2016)

5. Some host railroads require 2 locomotives, so even if the train could be hauled by 1, it would have 2 on it.

Also the Chargers, being owned by the states, are only going to be used for 'Corridor' service. So you'll only see them on the short-haul trains.

peter


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## west point (Jan 26, 2016)

But if ( that's a very big if ) Amtrak can get the funds we can probably expect Amtrak to also buy Long Distance chargers.( bigger fuel tanks and 1000 KW HEP )


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## PerRock (Jan 26, 2016)

west point said:


> But if ( that's a very big if ) Amtrak can get the funds we can probably expect Amtrak to also buy Long Distance chargers.( bigger fuel tanks and 1000 KW HEP )


Amtrak will (and legally has to) buy said new locomotives from the lowest bidder; that's the way American government agency buy things. So it's entirely possible that EMD or MPI ends up with the contract rather then Siemens. EMD is in fact working (or at least suing) very hard to get back into the passenger locomotive business.

peter


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## willem (Jan 26, 2016)

I am not and have not been a Contracting Officer. What follows is my understanding.

Even if Amtrak is a government agency for the purpose of buying locomotives, the Federal Acquisition Regulation does provide the Contracting Officer with tools he or she can use to award a contract on a basis other than low bid. The selection criteria need to be stated clearly in the solicitation document, and it does not need to be low-bid. Even on a low-bid solicitation, the Contracting Officer has an out, in that a bidder can be found not qualified and thus rejected.

With that said, selecting the low bidder is usually easier and is common practice.


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## Ryan (Jan 26, 2016)

^^^ Also not a Contracting Officer, but have to work closely with them, that's a pretty good summary.


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## Thirdrail7 (Jan 26, 2016)

west point said:


> 4. DC traction motors ingest fine snow and short out many times where as AC very seldom. *Note how well ACS-64s operated in the just past snow storm using AC traction motors. *


Oh man did that make my day...and Snoopy's too!!

https://www.youtube.com/watch?v=LJpXI37JYEI


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## jis (Jan 26, 2016)

So what's the real scoop Thirdrail?


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## Caesar La Rock (Jan 26, 2016)

Another thing to point out, just about every MU and electric locomotive that has operated on the corridor since the wires first went up was AC traction. I mean sure, there were was equipment that used Ignitron Rectifiers and Silicon Rectifiers, but nonetheless AC.

As for the P42s vs. Chargers, I'd wait until one of the locomotives is in service before we judge the ups and downs of both locomotives. Comparing an electric locomotive to a diesel is oranges and apples after all.


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## jis (Jan 27, 2016)

I guess you use the term AC traction to refer to how the power is delivered to the engine. I think the point being made earlier in the thread was about the difference between AC or DC traction referring to the nature of the motors that drive the wheel. In that sense both the Sprinter and the Charger are AC traction and almost apples to apples as far as adhesion and tractive efficiency - the hallmark of AC traction goes. Indeed their trucks are possibly quite similar too if not identical.


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## Caesar La Rock (Jan 27, 2016)

In the case of AC vs. DC, previous posts pretty much made it clear that AC is superior to DC. As for AC and how the power is achieved from the engine or multiple unit, yep.


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## CCC1007 (Jan 27, 2016)

Considering the last DC freight locomotive for the North American network was delivered in 2010, it is very likely that the next order will be for AC locomotives.


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## neroden (Jan 27, 2016)

FWIW Amtrak is not a government agency for procurement purposes, it's a government-owned corporation. Amtrak is quite capable of making a no-bid exercise of an option on the Chargers, as long as there's a legitimate reason to do so, which there is. Amtrak is quite likely to write the long-distance locomotive spec to require such exact compatibility with the Sprinters (which Amtrak will probably be maintaining) that nobody else will want to bid anyway. Amtrak doesn't want to deal with a whole bunch of incompatible types of parts.

"Brushed DC motors" such as the P42s use are essentially obsolete; nobody uses them for anything any more, except in very cheap junk. Permanent-magnet DC motors are used in many places but powerful ones require expensive rare-earth magnets. AC induction motors are the standard which have taken over for the majority of high-power applications. They were actually invented by Tesla over 100 years ago, but to control their speed, they have to be transitor-controlled and so most practical uses required the invention of MOSFETs or IGBTs before they could be used. Now that those are standard, AC induction motors are standard.


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## PVD (Jan 27, 2016)

To both Neroden and JIS point, even in systems where the power delivered is via dc 3rd rail like NYC subway, MNRR, and LIRR, newer railcars use AC motors. I'll add the (3rd rail capable) P32-DM sibling of the P42 which also has AC motors.


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## bretton88 (Jan 27, 2016)

I should note that there's already a sizable option for LD diesels in the existing charger order. So Amtrak in a way has already contracted this out, but who knows if they'll exercise their option on the Chargers.


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## afigg (Jan 28, 2016)

bretton88 said:


> I should note that there's already a sizable option for LD diesels in the existing charger order. So Amtrak in a way has already contracted this out, but who knows if they'll exercise their option on the Chargers.


Yes, there is an option in the Siemens Charger contract for up to 150 diesels in LD configuration with the specs spelled out. Amtrak was heavily involved in the writing of the specs and the contract bid process, so can't claim that the Siemens Charger contract award was not ok with Amtrak. So, if Amtrak wants to buy some new diesel locomotives for the LD and medium range eastern corridors, they already have the contract vehicle in place for how many years the options are good for. All Amtrak has to do is negotiate final terms, prices, and delivery schedule with Siemens. Which is a quick process compared to issuing an RFP and go through the long bid process again.

Unless there are problems with the Siemens Chargers delivered to the states, no reason to expect Amtrak to do anything other to buy Charger locomotives if or when it can scrounge up the funds for a first batch locomotive order to start replacing or supplementing the shrinking fleet of working P-42s.


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## cirdan (Jan 28, 2016)

neroden said:


> They were actually invented by Tesla over 100 years ago, but to control their speed, they have to be transitor-controlled and so most practical uses required the invention of MOSFETs or IGBTs before they could be used. Now that those are standard, AC induction motors are standard.


Much of the early electrification in Italy (pre WW1) was three-phase AC and this was long before any meaningful rectifiers were available. They just used massive resistors to control the speed and also did tricks with parallel and series switching not too dissimilar to what was happening in the DC world, but just more complex. Italy later switched to all DC. In Germany there was a test electrification in circa 1903 that saw speeds of over 125mph being demonstrated, the fastest any train had done at that time. They used three phase motors in direct connection but the controller was not on the train but by the lineside. The lineside station thus dicacted the train's performance by varying the supply voltage and frequency. The only thing the train engineer could do was disconnect the power and apply the brake. There are still a small number of fixed frequency three-phase electrifications of that generation in use today, however. Mostly mounatin cog railways in Switzerland and France.

However, its only thanks to silicon that an efficient control method is available. The revival of AC traction motors began in the 1970s but didn't really catch on in a big way until the late 1980s.


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## CCC1007 (Jan 28, 2016)

afigg said:


> bretton88 said:
> 
> 
> > I should note that there's already a sizable option for LD diesels in the existing charger order. So Amtrak in a way has already contracted this out, but who knows if they'll exercise their option on the Chargers.
> ...


150? I thought there were 225 options.


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## west point (Jan 28, 2016)

The DC to AC traction will progress at a financial best practice speed.

1. As of now only a very new few locos being built have DC traction and we can probably expect those RRs especially the few commuter rails such as TriRail that bought DC will regret that decision.

2. The conversion of some DCs to ACs that NS has started may mean one more coffin nail in DC traction.

3. Now AC traction motors last longer between overhauls and have fewer failures per 10,000 miles.

4. Biggest limitation now is that the total cost for an equal HP package of DC traction is still less than the AC including the inverters. As long as newer inverters are backward compatible to older inverters change over can be faster.

5. When inverter tech which is still in infancy reduces total cost of AC to near DC then final nails will be driven. Note even BNSF C$ that they have received can be upgraded to C-6s

6. With the downturn in traffic and storage of many older DCs that is another lowering of needed overhauls.

7. Close monitoring of the contractors that overhaul DC motors will give an advance notice of DC's demise.

8. As the various RR's DC locos reach retirement, end of lease, wrecks, etc the surplus DC traction motors can be transferred to operating DC locos further reducing needed overhauls.

9. Expect that spare parts, storage space for parts, and extended warranties will be part of any contract. Performance metrics will be in a contract as well and the MTBF and enroute failure rate will be in the contract. So if those metrics are not met Amtrak will require that they be made financially whole and supplier will probably have to provide additional locos. These provisions may be why the ACS-64s have performed so well ?


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## Fan Railer (Jan 28, 2016)

CCC1007 said:


> afigg said:
> 
> 
> > bretton88 said:
> ...


225 includes the 75 commuter configured locomotives for state corridor service. 150 is the number of long distance locomotives that would begin replacement of the Genesis fleet.


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## west point (Jan 28, 2016)

Why build two different versions of the Chargers. Probably the only differences will be HEP capacity, fuel tank capacity, PTC installations. To not build all Chargers the same increases parts. Not having the greater HEP is just not very smart ( dumb ? ) Of course keeping the SD locos will tend to keep them from getting lost in the greater Amtrak system. But who knows what the Passenger system will be like in 10 years ?


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## neroden (Jan 28, 2016)

cirdan said:


> neroden said:
> 
> 
> > They were actually invented by Tesla over 100 years ago, but to control their speed, they have to be transitor-controlled and so most practical uses required the invention of MOSFETs or IGBTs before they could be used. Now that those are standard, AC induction motors are standard.
> ...


Are you sure those weren't using *synchronous* AC motors or *universal* AC/DC motors? (Look at Wikipedia for a long, long list of motor designs). For asynchronous AC induction motors, you change the speed by changing the *frequency* of the electricity and that's a humungous pain in the neck without modern electronics.
There are actually a lot of motor designs. Electronically commutated DC motors, usually using permanent magnets, are becoming standard in small electronics now. The reason they're less common in big applications is that you need more powerful magnets than cheap iron magnets can provide.


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## neroden (Jan 28, 2016)

west point said:


> Why build two different versions of the Chargers. Probably the only differences will be HEP capacity, fuel tank capacity, PTC installations. To not build all Chargers the same increases parts. Not having the greater HEP is just not very smart ( dumb ? ) Of course keeping the SD locos will tend to keep them from getting lost in the greater Amtrak system. But who knows what the Passenger system will be like in 10 years ?


It's probably cheaper to have a smaller fuel tank. I expect the states didn't want to shell out for the bigger-fuel-tank design.
I'm not even sure the HEP capacity is different. The only difference I know of for sure is the fuel tank size, which allows the "long-distance" model to go farther before refuelling.


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## CSXfoamer1997 (Feb 1, 2016)

west point said:


> Why build two different versions of the Chargers. Probably the only differences will be HEP capacity, fuel tank capacity, PTC installations. To not build all Chargers the same increases parts. Not having the greater HEP is just not very smart ( dumb ? ) Of course keeping the SD locos will tend to keep them from getting lost in the greater Amtrak system. But who knows what the Passenger system will be like in 10 years ?


Think of it. Building one version for regional services, AND another for Long Distance services. Even though these locomotives are said to be very fuel-efficient, the long distance locomotives would need more fuel to last the entire trip [hint: it would have a larger fuel tank (2,200 gallons on the long distance locos vs 1,800 gallons on the regional locos)] AND would also need to supply more HEP (Head-End Power) to the cars, because the long distance trains could possibly be longer than the regional trains [hint: feeding 1000kw of HEP from the long distance locos vs feeding 800 kw of HEP from the regional locos].


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## jis (Feb 1, 2016)

Is it really worth tinkering around with two different alternator for HEP modules that occupy the same physical space but differ in capacity by 200kw? Just wondering.

It seems to that the fuel tank must be the significant issue requiring more physical space.


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## cirdan (Feb 1, 2016)

jis said:


> Is it really worth tinkering around with two different alternator for HEP modules that occupy the same physical space but differ in capacity by 200kw? Just wondering.
> 
> It seems to that the fuel tank must be the significant issue requiring more physical space.


The alternator? I can sort of see the point.

But the fuel tank? This is not a hi-tech part that's going to need regular replacement. Neither can I imagine that fuel tanks are extremely costly to design. I don't think having two different types is going to break anybody's neck or blow their budget.

These days everything is about platform. Ultimately you can even argue the Charger and the Sprinter are the same platform with localization. Platforms are about stadardizing the costly and engineering-intensive bits while allowing customization on the comparatively low tech stuff.


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## jis (Feb 1, 2016)

There is definite need for two different fuel tanks if that is what the customer desires. I suppose the HEP alternator module will just be either strap configurable or software configurable to be 800kw or 1Mw. No need to create two separate pieces of hardware.


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## west point (Feb 5, 2016)

A point about the ACS-64s. The 64s have two transformer - rectifier - inverter systems. Each inverter supplies 2 traction motors and one of the 2 HEP 1000kw supplies. If the sprinters could use the same inverter then parts compatibility would be the same for that system. .Also the 1000Kw HEP. As well each AC traction motor could be the same as the -64s but power normally spread between the 4 axels. Then if one or more traction motors became inop the other 2 or 3 could provide the same HP. Of course starting train from stop would need to be slower to prevent wheel slip.

But it is probably too late to implement such a design ?


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## CSXfoamer1997 (Feb 15, 2016)

jis said:


> I guess you use the term AC traction to refer to how the power is delivered to the engine. I think the point being made earlier in the thread was about the difference between AC or DC traction referring to the nature of the motors that drive the wheel. In that sense both the Sprinter and the Charger are AC traction and almost apples to apples as far as adhesion and tractive efficiency - the hallmark of AC traction goes. Indeed their trucks are possibly quite similar too if not identical.


The Chargers will use the same trucks as the ACS-64's: The Siemens SF4 Bogies (or trucks).


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