I know there were some forms of HEP going back to the early streamliners.

And I know that commuter trains were the first to convert because the old system was such a pain: Without sustained high speeds, axle generators didn't create enough power to light the train let alone A/C it so one needed trainlined power from a suitably equipped locomotive as well as a steam generator for heat. And when A/C came in, it was usually via individual Ice Engines. HEP wipes out a huge amount of gear. And the captive fleet, with no need to be compatible with the rest of the country, made conversion simpler.

But who was the first to do the type of HEP we have today, with 4 sets of cables, 480V 3Φ, those particular connectors, the safety circuit the way it works etc.? If you wanted to take a current car back in time and successfully insert it amidst a train of that period and have it all work, who is the earliest you can go back to?

(Surely not LIRR with 600VDC HEP!)

The Northern Pacific had Dynamo Express cars built in 1915.

http://www.gn-npjointarchive.org/GeneHa ... T_0476.jpg

http://www.gn-npjointarchive.org/GeneHa ... T_0472.jpg

They used steam from the Engine to run a turbo-generator.

I assume 32-VDC.

I don't think OSHA would approve.

And for you Spinal Tap fans, it goes to 12!

-Hudson

Cool and thanks but that's lighting power; surely they were still using steam for heat. Although it is power from the head end I wouldn't call it HEP unless it was an all purpose power source (granted we can skip over A/C in that time frame). Still would like to know who designed the modern system.

I think it was the C&NW in 1960, with the 152 car order of gallery cars. I recall that these were the first "all-electric" commuter cars. Previous cars on the Burlington (early streamliners & commuter cars) used HEP for lighting & a/c, but still had steam heat.

There were a great many of different systems for Air Conditioning on passenger cars, some more successful than others. It really depended on the service demands of the car.

I agree with the assessment that C&NW was probably the first to go to full HEP, on the push-pull gallery trains (not the first order of just coaches, those were converted when the cab-cars came out), the one caveat is that the C&NW gallery train's HEP is wired differently. If you plug a C&NW gallery car into a "standard" HEP source without changing the electrical plugs or something in the cars, you can and will blow the generator.

The 480vac 60hz 3 phase delta, is defined by common USA power standards. To be specific, the ability to buy motors, lighting, controls etc. from McMaster-Carr or your friendly local electric supply; and the ability to trivially provision shore power from local utilities.

Why 480 specifically, probably has to do with ancient Roman electrifications and the width of a horse's rump :)

The delta configuration was chosen to make the power be ungrounded. This reduces wire count by one and allows easy detection of ground faults. In fact, grounding of any leg is considered to be a ground fault.

Even moreso, the reason to be ungrounded is a throwback to early battery MU controls on electric traction. Traction power must, necessarily, use the chassis of the vehicle as its neutral/return because the tracks are the return. The MU controls and battery power are intentionally isolated from (not grounded to) the chassis. Why? Because the MU controls are trainlined. If they also trainlined chassis ground, then anytime a car hit rusty rail, its traction motors would try to ground through the trainline control wires. Now you have current running around places never intended at voltages not designed. That's why controls are ungrounded.

How is this Amtrak's problem? It has electric operations. Imagine a meatball goes up on some rust and tries to pull traction ground through the HEP cable. It could lift their voltage as high as the 25kv trolley wire. That's why HEP is ungrounded.

The connector was probably the result of a shopping expedition into commercially available connector plugs at that rather considerable power rating, size, mountings and suitability for railroad service. I bet their options were limited.

The safety circuit is simply form following function. How else are you going to do that? Well there are a lot of ways, but this way is dog simple.

Not all setups use 4-cable. There is some 2-cable and even 1-cable out there. Also Canada does the same system but pushes the voltage to 575v to get more power through the same wires (rated for 600v). This allows them to support those long transcon trains in cold months.

Somewhere in the boxes I have a binder of Amtrak bulletins. One covers the use of HEP cars in mixed consist trains and if memory serves it states that for the safety of the operators the HEP system was designed to be incompatible with previous systems. The use of 480V was higher than previously used to allow for more power to be transmitted than the previous systems.

Now, older cars did use 220V3P power like the Budd built full domes for the Great Northern. I have seen warning tags in the electric lockers of flat top cars stating that two full domes could be train lined together or thru a DC coach with a three wire train line as long as the train line switch on the coach was open. Keep in mind this was using the PN inter diaphragm plugs that are exciting when they come loose on a DC car. Imagine 220V AC swinging around at 50mph? I had seen a three wire jumper and wondered what it was for before I saw the tag.

Disclaimer. Its been 15 years since I was in an electric locker or even cared about one so my recollection is most likely defective. I have gratefully forgotten the nuances of reverse current relays and the associated junk.

Robert:
AFAIK Canada is not 575V. Only GO Transit is. VIA and so far as I know, everyone else, is 480V just like here. Their cars, however, do not common all sets of cables. My understanding, subject to correction, is that the two sets on each side are separate and a car can be set to draw from one side or the other. The locomotives are set up to power one side or the other or both. This allows a train with two units to have both powering the train, one for one cars drawing one side, one for the other.

Normally you can only have one power source since US cars have everything commoned together. (Amtrak's P30CH's did have HEP gensets, two per unit, which could and did synchronize so multiple sets could power a train.)

The "shopping expedition" for a connector seems unlikely. For a connector that can carry heavy current at 480V (presumably the actual rating is higher), sure, maybe. But don't forget there's also the safety circuit connections. Was that really an existing product? I suppose there could be some other application that uses a safety circuit.


Bulby:
Yes, I know there were many A/C systems but what else was ever used on commuter trains? Probably just Ice Engines unless someone was using steam ejector. This is in the context of my saying that the pre HEP way was a bigger pain in the rear on commuter trains than it was on LD trains which is one reason (captive fleet is another) that they went HEP first.

Did Diesel locomotives already use that style of connector for MU connections?
But why and how did modern commuter agencies, except for Maryland, come up with slightly
different pin assignments? That's a complaint I heard from an Amtrak official about assembling
the Thanksgiving Holiday trains with various borrowed equipment.

The MU jumper is a 27 pin connector that can only take 72VDC. It is also larger in diameter than the HEP plugs.

The big issue with the "different connectors" as I understand it, has to do with the polarity of the cars, the actual jumpers will plug in just fine... Just don't energize them, or you're going to start blowing circuits. Remember HEP is three phase and thus a little bit more complex.

If your cars are normally captive, it doesn't much matter if you use a slightly different arrangement of the phases to suit your needs.

Hmmmm, BN-3 sure seemed to work just fine with IRM's CNW gallery cars.

No explosions, no special cables, no blown generator, no rewiring.

Regarding phase rotation sequence on Chicago RTA equipment fleets, the previous posters are all correct depending on what fleet of cars and what period of time.

There were both rotation sequences in use in Chicago. The RTA F40PH units were equipped with a phase sequence reverser, which was a Siemens motorized switch similar to the MB transfer, and this allowed changing output sequence at the HEP cabinet so they could operate with either fleet.

Some cars were sold out of the fleet and ended up in other operations with incompatible power sources where they caused problems. Other cars had been modified prior to sale.

So depending on what equipment and what time period you are all correct.

PC

Any idea who was the first to use the modern system with those particular connectors, the 4 sets of cables, the safety circuit, etc.?

Not sure I'm buying the idea that those connectors were simply selected out of a catalog of already existing designs but I could be wrong.

I think that C&NW 151 (preserved at IRM) may have some leads that would help in answering the question as to who originated HEP standards. As I recall, this car has a plate in the vestibule listing the patent numbers for the various devices used in the car. One of those patents may relate to the HEP or its components. Fortunately, a patent is relatively easy to look-up once the number is identified. Does IRM have any operators manuals for C&NW/CRI&P F-units rebuilt for commuter service, the MILW E-units delivered with HEP, or the Budd MILW and Rock Island Bi-Levels? These documents may have a list of patent citations as well. There may be some patent plates in the bi-levels remaining in Metra service, but I recall most disappeared in the past 10 years.

A related question - what HEP voltage and phase did the PRR Keystone trainset use? Does anyone know of any good photos (on-line or otherwise) showing its as-delivered HEP cables and connectors?

In regards to BN-3 / BN (WSMTD) 9919. I recall that IRM replaced the gen-set about 10 years after receiving it from BN. Does anyone know how the new gen-set varied from the one used in revenue service and if the HEP connectors were changed at this time as well. BN-3 / BN (WSMTD) 9919 has the distinction of being the last E-unit to be rebuilt for daily common-carrier service - its last rebuilding occured in 1988 (if I remember correctly) and was contracted to Wisconsin Central and carried out in Fond du Lac, WI.

I did a bit of research into HEP and other means of railroad passenger car power a couple years ago. Looking for the back story of all-electric power, I found some news items in Trains magazine for when CB&Q bought its first all-electric cars in late 1950.

http://www.utahrails.net/pass/dynamos-h ... commutehep

But, I could not find where the standards came from (cabling, connectors, etc.). But 480Vac, three phase, 60 cycle seemed to be an accepted standard for commercial power, at least in the U.S.

Don Strack
http://www.utahrails.net/