Acela - How does it run?

[Everydaymatters]

Can someone please explain how the Acela runs? Please explain it as if you are talking to a 12 year old who doesn't know the first thing about these type of things. Where does the power come from?

Betty

 

[Neil_M]

The power comes from the overhead wires which will be supplied from an external supply, either the main electric supply grid, or the railways own power generation plant.

On top of each power car/locomotive is a sprung framework called a pantograph which when raised by control from one of the cabs will come into contact with the overhead wires and a switch on the roof of the power car will close and connect the supply to the power cars transformer.

The transformer reduces the voltage down from 11,000 volts, which is too high to use in the motors that drive the train, to a more usable 1,500 volts (or so)

The motors are similar to that on a diesel loco,mounted on the bogie/truck and are geared to the wheels, and the engineer controls the speed of the train by increasing the voltage to the motors.

Too complicated? Too simple?

 

[George Harris]

Quick and short explanation:

The power comes from an overhead wire. there is a sringloaded device on the top of the trains that has a bar that slides against this overhead wire to take the electricity to the train. The return path of the electricity is through the rails. The electricity powers a motor attached to each axle. I do not know whether all axles are powered on these trains, but I think not.

There are web sites that will carry this explanation further, but I can't think of any right now. I will try ot find some later and get back to you.

****

Neil: obvously, I was writing at the same time you were.

****

A couple other thoughts:

On the northeast corridor, there are three voltages used:

Washington to New York: 11,000 volts, 25 cycle. System first installed by the Pennsylvania Railroad pre WW2.

New York area somewhere or other to New Haven CT, 12,500 volts, 60 cycle. conversion in frequency and slight increase in voltate in the last couple decades. Original overhead installed by the New Haven Railroad pre WW2.

New Haven to Boston, 25,000 volts, 60 cycle, installed by Amtrak.

The new part, 25kV 60Hz is regarded as the modern voltage/frequency. Sometimes called "coffeepot" frequency since it is the same as that used commercially. (In Europe the "coffeepot" frequency is 50 cycles per second.)

 

[the_traveler]

The transformer reduces the voltage down from 11,000 volts

... or up to 25,000 volts. (The northern part us the NEC uses 25,000 volts.)

 

[MrEd]

Acela - powerful electric propulsion engines save precious resources and reduce greenhouse gases. Trains consume 18% less energy per passenger-mile compared to airplanes, and 17% less energy than automobiles. Yet with two locomotives on each train, Acela generates enough strength and speed to get you from city to city safely and efficiently.

 

[Everydaymatters]

Thanks. I told my husband I thought it ran from big batteries in the power car. He rolled his eyes and told me not to tell anyone that.

 

[PetalumaLoco]

Short youtube video of Acela with good pantograph views.

In 2nd half you can plainly see overhead wires and pantograph to pick up electrical power.

 

[Neil_M]

Thanks. I told my husband I thought it ran from big batteries in the power car. He rolled his eyes and told me not to tell anyone that.

The power cars do have batteries but only for running stuff like lights and the controls in the cabs, and the control of the power car on the other end of the train.

 

[Green Maned Lion]

The electricity powers a motor attached to each axle. I do not know whether all axles are powered on these trains, but I think not.

Didn't we have a discussion about how the Acelas are or are not EMUs depending on your definition of EMU? I do believe all four axles on each power car are, indeed powered, but the train does not have distributed power (which is the way most Americans use the term EMU).

 

[Neil_M]

The electricity powers a motor attached to each axle. I do not know whether all axles are powered on these trains, but I think not.

Didn't we have a discussion about how the Acelas are or are not EMUs depending on your definition of EMU? I do believe all four axles on each power car are, indeed powered, but the train does not have distributed power (which is the way most Americans use the term EMU).

Electric Multiple Unit would indicate an ability to couple to another train of the same type,hence the use of the word 'multiple'....

 

[Joel N. Weber II]

Thanks. I told my husband I thought it ran from big batteries in the power car. He rolled his eyes and told me not to tell anyone that.

The Tesla Roadster is a lithium ion battery powered sports car with a nominal range of about 240 miles. It costs roughly $100,000. (Compare to maybe $20,000 for a perfectly good new gasoline powered automobile with otherwise roughly the same functionality, though Tesla claims in about 5-6 years they should have an electric car priced around $30,000, which taking into account energy costs might turn out to cost about the same as a gasoline car.) IIRC, roughly 1/3 of its weight is the batteries. I think it may very well be possible to scale that technology to commuter rail trains (although I'm not sure whether putting the batteries in only the locomotive and not the passenger cars will turn out to be practical), but getting the range to do a BOS to WAS run on batteries might be difficult.

Additionally, I believe that doubling the speed requires 8 times the energy to overcome the wind resistance, which may make using batteries in high speed trains while keeping the weight reasonable impractical.

 

[Green Maned Lion]

Electric Multiple Unit would indicate an ability to couple to another train of the same type,hence the use of the word 'multiple'....

Yes, that was the discussion we were having. And we also concluded, Neil, that while in europe the term is used, and perhaps more correctly so, to mean exactly that, in the US it tends to refer only to EMUs with distributed power.

 

[Neil_M]

Electric Multiple Unit would indicate an ability to couple to another train of the same type,hence the use of the word 'multiple'....

Yes, that was the discussion we were having. And we also concluded, Neil, that while in europe the term is used, and perhaps more correctly so, to mean exactly that, in the US it tends to refer only to EMUs with distributed power.

Americans in using wrong terminology shocker........ :lol:

 

[PRR 60]

The power comes from the overhead wires which will be supplied from an external supply, either the main electric supply grid, or the railways own power generation plant.

Amtrak does not own any power generation. They have a dedicated 25hz hydro turbine at the Safe Harbor Dam in Pennsylvania, but the facility is not owned by Amtrak.

 

[battalion51]

IIRC there was a power plant that was owned by the New Haven Railroad for what is now Metro North.

Also, every locomotive and passenger car has batteries. Just like a car, in order to start the diesels you need electricity, as well as backup in case of emergencies, and to spot the engine when the motor is shut down. The cars have batteries to keep essentials like emergency lighting and markers on in case of a HEP failure.

 

[rrdude]

It's pretty simple, it's a "trolley car, on STEROIDS"

 

[Guest_espeefoamer_*]

It's pretty simple, it's a "trolley car, on STEROIDS"

It's what a GG1 woulde be when crossed with Superman.

 

[jis]

The thought of crossing Eric with a Superman boggles ones mind :lol:

 

[rrdude]

The thought of crossing Eric with a Superman boggles ones mind :lol:

You HAD to do that eh? You had to paint that image for us? Well, I for one would LOVE to see a flying GG1 coming to the rescue................

 

[DET63]

Can someone please explain how the Acela runs? Please explain it as if you are talking to a 12 year old who doesn't know the first thing about these type of things. Where does the power come from?
Betty

Thanks. I told my husband I thought it ran from big batteries in the power car. He rolled his eyes and told me not to tell anyone that.

A 12-year-old has a husband?