Amtrak ACS-64 Sprinter Discussion

[gokeefe]

Here's another alternate theory to "it's bad track" ... Just imagine what kind of strains occur on the HEP from the Amfleet cars. ACS-64 has an integrated bus. Think about all the old fashioned high power draw mechanicals on those Amfleet cars. The second stage heat (electric resistors) in particular would have an enormous power draw in the winter. During exceptionally cold weather the draws from that system running alongside everything else could have power spikes during on/off cycles. This would be especially true if it happened all at once when leaving a sheltered area and suddenly going into the cold.

You might trip the thermostats on every single car in the set within 5-10 seconds of each other. 8 entire cars of electric heat flipping on all at once could be some huge watts. Combined with voltage fluctuations this might be enough to freak out the control systems.

Yet another reason to look forward to new cars. I would also note that as of yet we have never heard a complaint of "they can't pull" or "dumps the air for no good reason" or "derailed when it shouldn't have". HHP-8 and E-60 both had some of those issues as I recall from previous discussions.

[mcgrath618]

This makes one wonder if SEPTA's fleet is destined for the same future. Obviously the engines operate in different environments in terms of speed, distance travelled and stopping patters, but I doubt that SEPTA is better at preventive maintenance. SEPTA's engines are newer though, so they might have a few extra years for corrective actions.

Leaving MARC and the hippos aside, NJT is the only other commuter agency to operate significant number of electric engines. Were the ALP-46As any better at the same point of their lives with NJT? I can't imagine this being the case. NJT has not been good at maintenance for quite a while and is known to push their equipment to the limits.

I disagree. Preventative maintenance is probably the one thing SEPTA excels in.

[David Benton]

If the Sprinter problems were Siemens fault , why would Amtrak even consider buying Chargers???

[east point]

To follow on with what gokeefe said: Could it be that the regenerative braking function is being exceptionally hard on the ACS-64s electronics. Does anyone know if regeneration is used on any of the Siemens motors in Europe ? Not saying it happens but the many cycles from pulling to regeneration braking and the switching of regeneration power to power the HEP might cause the voltage spikes and that would not only be from each train's own power consumption but the many other trains going thru those cycles at the same time.

Is there any one who has first hand knowledge of the power and voltage recorders on each of the various divisions of the CAT power ? How smooth is the power and has Amtrak enough smoothing hardware for the use going on ? Does it affect ACELAs as well. What does the various commuter agencies also cause as well ?

EDIT ----- Just realized that the technology for switching to regeneration braking supplying HEP is new and as far as I know this is the first time it has been used ? That is both ACS-64s and SC-44s .

[Backshophoss]

Both the P32-DM and the DM-30 use dynamic braking to supply the HEP inverter when in 3rd rail gaps.
The DE/DM-30 have capacitors in the DC Link to the inverters.
The Dual mode Charger is hung up on the "Energy storage module" design and weight it adds to the unit.

[8th Notch]

The 618 just quit on 161 not even 10 miles out of Boston....

[SRich]

To follow on with what gokeefe said: Could it be that the regenerative braking function is being exceptionally hard on the ACS-64s electronics. Does anyone know if regeneration is used on any of the Siemens motors in Europe ? Not saying it happens but the many cycles from pulling to regeneration braking and the switching of regeneration power to power the HEP might cause the voltage spikes and that would not only be from each train's own power consumption but the many other trains going thru those cycles at the same time.

Is there any one who has first hand knowledge of the power and voltage recorders on each of the various divisions of the CAT power ? How smooth is the power and has Amtrak enough smoothing hardware for the use going on ? Does it affect ACELAs as well. What does the various commuter agencies also cause as well ?

EDIT ----- Just realized that the technology for switching to regeneration braking supplying HEP is new and as far as I know this is the first time it has been used ? That is both ACS-64s and SC-44s .

But there is one big difference between the ACS-64 and SC-44 and that is powersource. A SC-44 is a powerplant and has his own alternator/generator and with regenerative braking the control system reduce the power of the alternator as needed and a the exces power go to HEP. ACS-64 draw power from a wire who is fed by a TSO. So when a ACS-64 brakes then the sytem must divert the exces power to HEP ore back to the catenary . The control system must work harder and faster, depend of HEP load and grid receptiveness. And the last is the problem. Grid is never stable it always fluctuates.

[amtrakhogger]

Both the P32-DM and the DM-30 use dynamic braking to supply the HEP inverter when in 3rd rail gaps.
The DE/DM-30 have capacitors in the DC Link to the inverters.
The Dual mode Charger is hung up on the "Energy storage module" design and weight it adds to the unit.

FWIK, P32ACDM’s do not have dynamic brake available in 3rd rail mode.

[gokeefe]

Although the Amtrak OIG wasn't fully satisfied with the approach to spare parts it does appear that Siemens is "on the hook" for guaranty payments if engine availability falls below a certain threshold.

[Tadman]

Would like a better definition of duty cycles. Are you meaning train assignments?. Or are you meaning train stops?. Or are you referring to the many changes in MAS that the motors are subject to combined with the train stops ?
The airline industry defines duty cycle as one take off and landing. Also one rejected take off.

Duty cycle is how hard equipment is used over a day. How heavy is the load, how many starts, how hard it accelerates and brakes, temperatures and conditions encountered, how many trips in a day.

Here’s a good comparison: the AEM7 here probably made 2-3 round trips per day, 125mph, 8 cars, 20 stops per turn, hard acceleration and braking, tight schedule. A similar Swedish RC6 on a 90-series train to the far north makes 1 run per day, cruised under 100, maybe 8-10 stops all day, gentle accel and braking, only six cars north of Kiruna and often double headed splitting the load.

One could accurately describe the duty cycle of the AEM7 on NEC as much more intense or severe. The actions generate more heat, the moving parts have less time to dissipate that heat, and there are more structural stresses on frames, couplers, etc...

There’s some rule of thumb out there that says if you drop the average temp of a electric motor by 10%, you can double the life span. (Nasadowsk, feel free to adjust my statement here).

TLDR it’s not just about speed or pulling capability, it’s about how much the train gets to that top speed and how much available pulling capacity is used.

[David Benton]

Thats a different definition of duty cycle than what is applied to electric motors. Maybe it applies to American railroads , I don't know.
a duty cycle is the amount of time a motor can run in a given time period . A motor that can run continuously has a 100% duty cycle . A small welder may only have a 10 % duty cycle,meaning you can only weld full bore for 6 minutes in a hour. They will usually have different duty cycles for different time lenghts , a motor may be able to go to 200 " for 30 seconds for example. The cycle may be derated in high temperatures , and increased in cold pressures. the main cycle might be at 20 degrees celcuis , and ratings change with temprature variations to that.
i would have thought a duty cycle for a locomotive would be how many hours per 24 hours it can be used, or is used.

[frequentflyer]

Would like a better definition of duty cycles. Are you meaning train assignments?. Or are you meaning train stops?. Or are you referring to the many changes in MAS that the motors are subject to combined with the train stops ?
The airline industry defines duty cycle as one take off and landing. Also one rejected take off.

Duty cycle is how hard equipment is used over a day. How heavy is the load, how many starts, how hard it accelerates and brakes, temperatures and conditions encountered, how many trips in a day.

Here’s a good comparison: the AEM7 here probably made 2-3 round trips per day, 125mph, 8 cars, 20 stops per turn, hard acceleration and braking, tight schedule. A similar Swedish RC6 on a 90-series train to the far north makes 1 run per day, cruised under 100, maybe 8-10 stops all day, gentle accel and braking, only six cars north of Kiruna and often double headed splitting the load.

One could accurately describe the duty cycle of the AEM7 on NEC as much more intense or severe. The actions generate more heat, the moving parts have less time to dissipate that heat, and there are more structural stresses on frames, couplers, etc...

There’s some rule of thumb out there that says if you drop the average temp of a electric motor by 10%, you can double the life span. (Nasadowsk, feel free to adjust my statement here).

TLDR it’s not just about speed or pulling capability, it’s about how much the train gets to that top speed and how much available pulling capacity is used.

Excellent post.

So are the Sprinters doing the same 2 or 3 roundtrip cycles as the AEM7s?

[rvlch]

A directly on point historical discussion of American electric locomotive design practice and performance in the context of the NE corridor is occurring concurrently in the PRR group on groups.io at https://prr.groups.io/g/PRR/topic/7131 ... &allview=1.

[Tadman]

Thats a different definition of duty cycle than what is applied to electric motors... duty cycle is the amount of time a motor can run in a given time period . A motor that can run continuously has a 100% duty cycle . A small welder may only have a 10 % duty cycle,meaning you can only weld full bore for 6 minutes in a hour.

That's duty cycle as specifically applied to electric motors. Often though, as in the case of a welder, locomotive, or crane (my business), there are more concerns than just run time even though a motor is at the heart of the machine. Motor starts and stops can be critical because of heat buildup and geartrain shock. Also loading on the motor - in cranes, a five ton crane is much different if it' picks up rated capacity at each lift versus staying below 50% capacity on most picks.

Back to the railroad, my swedish analogy was intended to show the difference between very similar locomotives, and why they'll probably continue to see the RC6 up north, while the AEM7 is retired. The AEM7 had a lot more stops and starts, a lot more 8-car trains, and a lot more 125mph use. All that wears on a train lifespan far more than just run time.

We also see this in aircraft maintenance requirements, which are based as much on landing cycles as they are on flying time. When a piece of equipment operates at "crusing speed", it's a low-stress environment provided most ambient factors like temperature, dust, acid, etc... aren't out of control. Takeoffs and landings are the most stressfull time for an aircraft - full throttle, hard braking, lots of heat generated, maximum forces exerted on wings and landing struts.

[gokeefe]

i would have thought a duty cycle for a locomotive would be how many hours per 24 hours it can be used, or is used.

It is but the point being made here is that the particular intensity of use is very high. The hour to hour comparison fails to fully explain how hard the engines are being pushed.