Amtrak and HEP

[Anonymous]

Tonight I went to see Amtrak. A few minutes after it arrived, the conductor went to the second engine (which was idling at a high RPM) and killed the HEP, this caused the RPM's to drop considerably. After about 30 seconds, the engine's RPM's accelerated slowly, but not to the previous level and the HEP was turned back on. I have seen this occur before while Amtrak is stopped at the station. What causes the engine to get to that high of an idle? Does it have anything to do with HEP?

[Anonymous]

Tonight I went to see Amtrak. A few minutes after it arrived, the conductor went to the second engine (which was idling at a high RPM) and killed the HEP, this caused the RPM's to drop considerably. After about 30 seconds, the engine's RPM's accelerated slowly, but not to the previous level and the HEP was turned back on. I have seen this occur before while Amtrak is stopped at the station. What causes the engine to get to that high of an idle? Does it have anything to do with HEP?

[Anonymous]

High RPM is needed to generate enough electricity for the passenger cars (Power, light, heating, air conditioning). In your case it probably was HEP.

[Anonymous]

High RPM is needed to generate enough electricity for the passenger cars (Power, light, heating, air conditioning). In your case it probably was HEP.

[Anonymous]

Thanks for the reply, Alaskaman. Much appreciated.

I understand that a higher RPM is required to produce HEP. However, I am still curious to know why the RPM dropped so significantly after HEP was restored. I don't know the "normal" RPM an Amtrak locomotive idles at, but to give you an example, prior to the HEP being turned off, the RPM was let's say 5000. After the HEP was restored, the RPM was 2000. Why so much of a difference? Does HEP actually make a locomotive idle at a higher RPM on an as needed basis? Just by the audible difference, I was given the impression that the conductor had to "reset" something by shutting down the HEP. Can anyone elaborate on this?

[Anonymous]

Thanks for the reply, Alaskaman. Much appreciated.

I understand that a higher RPM is required to produce HEP. However, I am still curious to know why the RPM dropped so significantly after HEP was restored. I don't know the "normal" RPM an Amtrak locomotive idles at, but to give you an example, prior to the HEP being turned off, the RPM was let's say 5000. After the HEP was restored, the RPM was 2000. Why so much of a difference? Does HEP actually make a locomotive idle at a higher RPM on an as needed basis? Just by the audible difference, I was given the impression that the conductor had to "reset" something by shutting down the HEP. Can anyone elaborate on this?

[Mookie]

Since you are talking in alphabet, I am going to guess that HEP is head-end power?

Close?

Mookie

[Mookie]

Since you are talking in alphabet, I am going to guess that HEP is head-end power?

Close?

Mookie

[oltmannd]

I don't know about the Genesis units, but the F40s could supply HEP from either the HEP generator which was gear driven off the engine or directly from main traction alternator. There is a switch to control which mode the locomotive operated in. In normal HEP mode, the engine turned at a constant 900 RPM and the HEP generator and gear drive were designed to make 60 Hz at this engine speed. In this setting, the engine could put out full 3000 HP, some going to the HEP gen and the rest for traction. In HEP only mode, the engine ran at approximately notch 6 engine speed so that 60Hz was coming out of the main generator. In this setting, the locomotive only made HEP - no traction.

With two F40s, the normal set-up was the lead unit would be in "freight" mode, with engine speed changing for all 8 notches and the trailing unit in normal HEP mode, with power split between the HEP and traction. But if there was trouble, you had options. Also, if you just needed the HEP for hotel power while laying over, it was more fuel efficient to put to use HEP only mode than spin the engine at 900 RPM.

[oltmannd]

I don't know about the Genesis units, but the F40s could supply HEP from either the HEP generator which was gear driven off the engine or directly from main traction alternator. There is a switch to control which mode the locomotive operated in. In normal HEP mode, the engine turned at a constant 900 RPM and the HEP generator and gear drive were designed to make 60 Hz at this engine speed. In this setting, the engine could put out full 3000 HP, some going to the HEP gen and the rest for traction. In HEP only mode, the engine ran at approximately notch 6 engine speed so that 60Hz was coming out of the main generator. In this setting, the locomotive only made HEP - no traction.

With two F40s, the normal set-up was the lead unit would be in "freight" mode, with engine speed changing for all 8 notches and the trailing unit in normal HEP mode, with power split between the HEP and traction. But if there was trouble, you had options. Also, if you just needed the HEP for hotel power while laying over, it was more fuel efficient to put to use HEP only mode than spin the engine at 900 RPM.

[CSSHEGEWISCH]

Metra has a similar situation in Chicago Union Station. Suburban trains receive light and heat or AC from station power prior to departure with the locomotive at idle. About 5 minutes prior to departure, station power is cut off and the engine speed increases to provide HEP for the train.

[CSSHEGEWISCH]

Metra has a similar situation in Chicago Union Station. Suburban trains receive light and heat or AC from station power prior to departure with the locomotive at idle. About 5 minutes prior to departure, station power is cut off and the engine speed increases to provide HEP for the train.

[Anonymous]

QUOTE: Originally posted by Mookie

Since you are talking in alphabet, I am going to guess that HEP is head-end power?

Close?

Mookie

You got it! It's Head End Power.
But i also have a question.
We have some GP40 locos with HEP. Do they have to have a seperate generator for HEP? Or is it the same one that produces power for traction motors?

[Anonymous]

QUOTE: Originally posted by Mookie

Since you are talking in alphabet, I am going to guess that HEP is head-end power?

Close?

Mookie

You got it! It's Head End Power.
But i also have a question.
We have some GP40 locos with HEP. Do they have to have a seperate generator for HEP? Or is it the same one that produces power for traction motors?

[Anonymous]

Thank you all for your replies! Definitely helps me to understand how HEP works.

[Anonymous]

Thank you all for your replies! Definitely helps me to understand how HEP works.

[dharmon]

So if HEP is produced by either a seperate generator or off of the prime mover, then how did older passenger cars get electricity? I understand that heat/hot water was provided from a steam generator located either on the locomotive or a steam generator car, but as far as electrical power, did each car have a generator powered by its wheels rolling down the rails or was that provided by the locomotive also?

[dharmon]

So if HEP is produced by either a seperate generator or off of the prime mover, then how did older passenger cars get electricity? I understand that heat/hot water was provided from a steam generator located either on the locomotive or a steam generator car, but as far as electrical power, did each car have a generator powered by its wheels rolling down the rails or was that provided by the locomotive also?

[oltmannd]

QUOTE: Originally posted by Alaskaman

QUOTE: Originally posted by Mookie

Since you are talking in alphabet, I am going to guess that HEP is head-end power?

Close?

Mookie

You got it! It's Head End Power.
But i also have a question.
We have some GP40 locos with HEP. Do they have to have a seperate generator for HEP? Or is it the same one that produces power for traction motors?

Probably a separate engine-gen set in the end of the long hood. Look for a truck-like stack near the end of the long hood. The F40s had separate generators, but they were gear driven off the prime mover. NJT converted theirs to separate diesel engine gen sets for two reasons: 1. you're not siphoning off traction HP to power the coaches and 2. the gear drives tended to be maintenance problems.

[oltmannd]

QUOTE: Originally posted by Alaskaman

QUOTE: Originally posted by Mookie

Since you are talking in alphabet, I am going to guess that HEP is head-end power?

Close?

Mookie

You got it! It's Head End Power.
But i also have a question.
We have some GP40 locos with HEP. Do they have to have a seperate generator for HEP? Or is it the same one that produces power for traction motors?

Probably a separate engine-gen set in the end of the long hood. Look for a truck-like stack near the end of the long hood. The F40s had separate generators, but they were gear driven off the prime mover. NJT converted theirs to separate diesel engine gen sets for two reasons: 1. you're not siphoning off traction HP to power the coaches and 2. the gear drives tended to be maintenance problems.

[oltmannd]

QUOTE: Originally posted by dharmon


So if HEP is produced by either a seperate generator or off of the prime mover, then how did older passenger cars get electricity? I understand that heat/hot water was provided from a steam generator located either on the locomotive or a steam generator car, but as far as electrical power, did each car have a generator powered by its wheels rolling down the rails or was that provided by the locomotive also?

Most pre-HEP coaches had DC axle driven generators. They had clutches that didn't pick up until a speed great enough to make enough voltage to charge batteries. The light and AC ran off the batteries. Most cars could be plugged into wayside power to keep the batteries up between trips.

Some cars, and most RR business cars today, had/have diesel engine gen sets located underfloor to handle heat/light/AC.

[oltmannd]

QUOTE: Originally posted by dharmon


So if HEP is produced by either a seperate generator or off of the prime mover, then how did older passenger cars get electricity? I understand that heat/hot water was provided from a steam generator located either on the locomotive or a steam generator car, but as far as electrical power, did each car have a generator powered by its wheels rolling down the rails or was that provided by the locomotive also?

Most pre-HEP coaches had DC axle driven generators. They had clutches that didn't pick up until a speed great enough to make enough voltage to charge batteries. The light and AC ran off the batteries. Most cars could be plugged into wayside power to keep the batteries up between trips.

Some cars, and most RR business cars today, had/have diesel engine gen sets located underfloor to handle heat/light/AC.

[dharmon]

Thanks Don,

That would explain all of the underbody equipment behind the skirts on the older cars that isn't there on the horizon/amfleet/etc.

[dharmon]

Thanks Don,

That would explain all of the underbody equipment behind the skirts on the older cars that isn't there on the horizon/amfleet/etc.

[coalminer3]

HEP was a big improvement from the technology that oltmannd mentioned. The fun part was trainlining power from car to car when axle driven stuff and/or batteries failed.

Also, in the circus train days of Amtrak, electrical and a/c systems from "foreign" cars were often unfamiliar to car folks; major heartburn when a failure occurred.

work safe



.

[coalminer3]

HEP was a big improvement from the technology that oltmannd mentioned. The fun part was trainlining power from car to car when axle driven stuff and/or batteries failed.

Also, in the circus train days of Amtrak, electrical and a/c systems from "foreign" cars were often unfamiliar to car folks; major heartburn when a failure occurred.

work safe



.

[Anonymous]

Some of the cars used blocks of ice for the air conditioning. A number of cars Amtrak inherited were equipped that way. Amtrak kept those cars on dedicated routes so that the ice would be available.

[Anonymous]

Some of the cars used blocks of ice for the air conditioning. A number of cars Amtrak inherited were equipped that way. Amtrak kept those cars on dedicated routes so that the ice would be available.