MU/ 4 diesel locomotives ....can the lead engine power traction axles in the other 3 without there prime movers running?
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The real train guys will post but imagine the amount of amps a cabling system would have to carry! WOW.
Engineer-Joe posted:The real train guys will post but imagine the amount of amps a cabling system would have to carry! WOW.
Thanks joe..as much as i googled i couldn't get an accurate answer. I am aware of the "slug" but thats where my knowledge ends.
I think the answer is yes and no. It depends how it's wired. I don't know if you can do that with standard units that have prime movers, that would be the no. If you have what is called a "slug", that has no prime mover, just traction motors, those are designed to take power from another engine.
This is Minnesota Commercial slug T-1 sitting next to the sanding tower.
Here's a BNSF slug being used at Northtown hump yard.
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Lets say 4 engines/ no cars needs to be moved from one siding to another...maybe 5mph max...i would think the amp draw would be minimal using one engine to move all.
It's probably standard info for the guys who know. All I can do is guess.
They could just move the other engines offline from one siding to the next I would guess? If they're building a train it would be easier to configure them for power and leave them?
I have to think that three diesels having their traction motors powered threw the cables would be some serious power draw.
I didn't even consider the slugs. So I maybe way out of line. See, I don't even know how one slug is powered. Does it use standard MU cabling or are there special wires to carry the current?
I remember reading how a single large diesel engine could provide enough power for a small city or town's power. So I would guess it maybe possible.
In today's efficiency movement, you would think it would be common to do if it was easy?
willygee posted:Lets say 4 engines/ no cars needs to be moved from one siding to another...maybe 5mph max...i would think the amp draw would be minimal using one engine to move all.
I believe the term would be "dead heading". You would just put them in neutral and drag them to where you wanted them. No power.
willygee posted:MU/ 4 diesel locomotives ....can the lead engine power traction axles in the other 3 without there prime movers running?
No. Only control voltage (74 volts DC) is passed through those 27 pin MU Jumper cables. The MU Jumpers are NOT able to carry ANY "traction high voltage/current".
willygee posted:Lets say 4 engines/ no cars needs to be moved from one siding to another...maybe 5mph max...i would think the amp draw would be minimal using one engine to move all.
Why bother trying to power the traction motors of the other three?
One locomotive has more than ample power to move three shutdown units in a yard environment.
Rusty
I've seen a train with seven locomotives and a handful of cars go by recently, only the lead locomotive appeared to be under power. I'm sure that most of those locomotives would not be powered and just being treated as rolling stock. Obviously, they were moving them to a location where they were needed, and that was the cheapest way to get them there.
willygee posted:Lets say 4 engines/ no cars needs to be moved from one siding to another...maybe 5mph max...i would think the amp draw would be minimal using one engine to move all.
Yes, the single unit moving a "dead" or "idling" unpowered consist would not be a problem. Such moves happen all the time within engine terminals.
Rusty Traque posted:willygee posted:Lets say 4 engines/ no cars needs to be moved from one siding to another...maybe 5mph max...i would think the amp draw would be minimal using one engine to move all.
Why bother trying to power the traction motors of the other three?
One locomotive has more than ample power to move three shutdown units in a yard environment.
Rusty
How are the electric traction motors able to achieve neutral...or is there just minimal drag?
"I remember reading how a single large diesel engine could provide enough power for a small city or town's power. So I would guess it maybe possible."
Let's see...
600 hp primemover, times 750 Watts (per HP) = 450 kW. A 200 amp home might use around 5 kW at a peak time. 450/5 = 90 homes. Figure an efficiency of 50% overall, including transformation and distribution losses, a locomotive might be able to power 45 homes, assuming Diesel running full bore, and the houses using minimal amperage.
Just some idle brain churning on a Sunday morning. The idea of re-purposing machinery is always an interesting engineering mental exercise, and seems to appeal to railroad enthusiasts.
Since it's a weekend, perhaps the moderator will allow a small diversion, Here's what big pieces of machinery can do towards energizing places and providing water to people:
willygee posted:Rusty Traque posted:willygee posted:Lets say 4 engines/ no cars needs to be moved from one siding to another...maybe 5mph max...i would think the amp draw would be minimal using one engine to move all.
Why bother trying to power the traction motors of the other three?
One locomotive has more than ample power to move three shutdown units in a yard environment.
Rusty
How are the electric traction motors able to achieve neutral...or is there just minimal drag?
On modern diesel electric units (post 1962 at least), the electrical switch gear components essentially have the traction motors "disconnected" from the main generator power, i.e. the electrical "power contactors" are OPEN. Only slight residual magnetic resistance between the armature and fields of the DC series wound traction motors, would be encountered, which would be no problem at all for one unit pulling/moving a fairly large consist of "dead" or "idling" units. With AC three phase induction traction motors on the current "AC Traction" units, there would be even less moving/rolling resistance.
The way any motor achieves neutral.
No power, no locomotion.
There is some drag, because of the gearing and mass of the locomotive, but not enough to justify powering it up just to move them from here to there.
Diesel trucks are spur gear drive, with a motor mounted on each driven axle. With everything turned off, there's an open circuit from the traction motors and no place for electricity to flow to.
BTW, the MU cables only carry control functions, not power.
Rusty
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I remember our light show kept growing in size. Back then, getting the power to handle the lights was serious. Some bars don't even have the wiring capability to handle themselves let alone a full size rock show. I had bigger cables than the bars had coming off the poles.
When we moved to theater sized venues, everything went up in scale. The cabling was called four 0 (ought) or something like that? The cables were huge to me. Our show wasn't even that large. I believe the house electrician said we were only drawing less than 20 amps per leg continuous, sound and lights. The peaks were largest when the lights get changed. You need a big capacity to handle those peaks. Sometimes they were not even realized.
So using that info with trains, the cabling to handle the current to three extra engine's traction motors (four or six each?), must be large. So what does each traction motor draw (peak)? You may think they don't need much power just to move at 5 MPH. There has to be the capability to handle max current whether it's used or not. That's just plain electricity rules. I can't see how that can be gone around? You can't use small cable and tell the engineer to not exceed their capability, like he could control that. If even one traction motor needed high current, I would think a small cable would fry well before the engineer could react. Your talking the speed of light, right?
Again, I'm just guessing! I just ran the sound board. I didn't tap the circuits anymore. Maybe the new AC traction motors are more efficient than the older DC ones? Just watch the TV shows when they tour the engine building plants. Look at the cable connections for the traction motors.
I do know the new LED lighting draws substantially less than the stuff we hauled around back then.
Rusty Traque posted:The way any motor achieves neutral.
No power, no locomotion.
There is some drag, because of the gearing and mass of the locomotive, but not enough to justify powering it up just to move them from here to there.
Diesel trucks are spur gear drive, with a motor mounted on each driven axle. With everything turned off, there's an open circuit from the traction motors and no place for electricity to flow to.
BTW, the MU cables only carry control functions, not power.
Rusty
Rusty,
That excellent photo of the DC traction motor gear without the gear case installed, is only applicable to DC traction motors (both EMD and GE). The much higher torque of the EMD (and I assume the GE) AC three phase induction traction motors must have angle cut gears in order to transmit the higher torque the axle "bull" gear and NOT slip the pinion gear.
Yes, the slug is powered from the mother unit through separate cables that carry current to the slug's traction motors. The cables are about 1-1/2" in diameter, over the insulation. The prime movers are removed from the slug and the space under the cut-down hood is usually filled with concrete for weight. The hood is cut down to provide viability from the mother unit for switching work. Since the units operate at low speeds, the prime movers in the mother unit can produce enough current for the traction motors of both.
Arthur P. Bloom posted:600 hp primemover, times 750 Watts (per HP) = 450 kW. A 200 amp home might use around 5 kW at a peak time. 450/5 = 90 homes. Figure an efficiency of 50% overall, including transformation and distribution losses, a locomotive might be able to power 45 homes, assuming Diesel running full bore, and the houses using minimal amperage.
You assume facts not in evidence. 
My house as 400A service, and from my electric bills for the three heat pumps, not to mention a couple of places that have baseboard heat, I can assure you that I'd be very happy with a 5KW usage at peak times! 
There is a 50KW transformer at the street that only powers my house, so PECO must know something that you don't. 
I railfan in western Ohio once in awhile, and down there CSX uses a lot of slugs on local freights. These are usually older GP30s and GP35s that have the Prime movers removed. They are paired with some more modern 4 axle such as a GP38 or GP40. I don't know how the cabling/wiring is setup.
The slugs are easy to spot because most of the louvres such as for radiators and even dynamic brakes have been welded over with plates. And the radiator fans are gone, I assume plates on the roof too. It is still nice to see the old units running. They sometimes lead too, so they must have cab controls on most. Ihave heard the the crews actually like running from the slug better because it is much quieter.
So the traction motors in the slug can be powered from the mother unit. I heard that they do not have as much speed capability.
This is how the Michigan Transit museum does it.
They have a old USAF locomotive that pulls the train when heading west. When the train is heading east, it provides power to the Lake Shore #11 that pulls the train as it heads east.
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They're running 600v DC cables under an L car and (what looks like a) caboose to the ex- South Shore car? That makes almost no sense. Personally, I don't see any power cables between the switcher and L car.
The diesel's engineer looks awfully intense if he's not actively doing the shoving. I suspect the "motorman" in the South Shore car is actually "tail-hosing" the train by operating the brakestand and the switcher is in reality moving the train.
Relying on a tail-hose man to be the engineer's eyes and ears during reverse operation is nothing new. The tail-hose man can make a reduction or dump the air if need be. IRM does it all the time with the steam train. The locomotive engineer still has to pay attention.
Rusty
Off-thread, but anything that proves my memory's not so bad cheers me up: Canadian National volunteered a couple of M420s to be generators last century. One was rolled down the pavement in Boucherville QC to be the town generator.
https://en.wikipedia.org/wiki/MLW_M-420
Anyway, what would the operations department say to a powered unit plus 3 slugs? And what about upgrading the amperage rating of the controls in the powered loco? Not necessary with just one slug?
Somebody correct me if I'm wrong, but was the original idea for slugs to spread the load across more traction motors and avoid burning them out in switching and/or low speed service?
P.S. Here's the CN locomotive parked in a Boucherville street supplying power after the '98 icestorm.
Slugs are used to provide more tractive effort for switching and low speed pulling, pure and simple. It has little to do with electrical load to the traction motors.
Rusty
Engineer-Joe posted:
Now there's some cables...now which one does what...
look at the lugs that go on these things!
I'm impressed anyways. Thinking what you have to deal with on the toys, these things are massive.
This post has had me thinking all day about POWER!
sorry about your luck......
Well you know which are the 3 air hoses from your models. The MU are the big ends up highest.
so it must be the middle sets with the black ends?
Why do I post? Sorry. couldn't help it. I don't have a clue actually!! I did stay at a Hol...................
Well i know one thing..at the end of the day i know a lot more on how all this works...in Joe's picture above is the cable on the left the 27 pin mentioned prior?
willygee posted:Well i know one thing..at the end of the day i know a lot more on how all this works...in Joe's picture above is the cable on the left the 27 pin mentioned prior?
No.
I believe Jack (HW) was talking about was the MU cable in the top of the picture above that one. That pic of the cable ends I just used to show what I call a lug looks like that handles the current. That cable on the left looks like a type of connector that's used for many other things. They even used them in sound systems. Not for heavy current.
Count the holes!
Ooops, HW posted!
