Hello.
Is it possible to power an overhead electric loco from a generator in a towed vehicle? I can't find an answer for this and am considering a layout which doesn't have any catenary but on which I would like to operate some of my overhead electric locos. I am just wondering if having a generator in a van/baggage vehicle behind the loco would, in real life, be able to provide the necessary power?
Many thanks in anticipation.
Chris.
You have a model locomotive that will only operate from overhead power?
I didn't know there was such a thing! :hmmm:
I'm not an electrical wizard or a railway professional (so may be completely wrong), but my amateur take is that theoretically it would be possible, but generator vans presumably only provide enough power for heating/lighting/cooking etc. in passenger accommodation. For enough juice to power a locomotive you'd basically need much of the innards of a diesel-electric loco (leaving aside the question of how you get the power to the electric loco other than tying the lead to the pantograph).
In real life, if a electric locomotive needs to be moved somewhere where there are no wires, you'd just put a diesel loco in front.
(https://live.staticflickr.com/2930/14617467748_0fa13fa7c0_z.jpg) (https://flic.kr/p/ogGkU1)
Sunday WCML Drag At Blackrod 1985 (https://flic.kr/p/ogGkU1) by Noted HSG (https://www.flickr.com/photos/87851292@N04/), on Flickr
Quote from: Bealman on September 18, 2019, 06:10:12 AM
You have a model locomotive that will only operate from overhead power?
I didn't know there was such a thing! :hmmm:
No I don't have such a loco. I do have a couple of locos with dummy pantographs but don't wish to install catenary. I was merely wondering if it were possible to create a 'generator van' to 'power' them.
Quote from: railsquid on September 18, 2019, 06:16:09 AM
I'm not an electrical wizard or a railway professional (so may be completely wrong), but my amateur take is that theoretically it would be possible, but generator vans presumably only provide enough power for heating/lighting/cooking etc. in passenger accommodation. For enough juice to power a locomotive you'd basically need much of the innards of a diesel-electric loco (leaving aside the question of how you get the power to the electric loco other than tying the lead to the pantograph).
In real life, if a electric locomotive needs to be moved somewhere where there are no wires, you'd just put a diesel loco in front.
Thanks railsquid. That is helpful. Surely it must be possible to have a diesel generator that can be plugged into the loco to power it. I am sure those who preserve 3rd rail locos have done it.
Generator vans in reality provided electric train heating, lighting. Ive only seen electric locos having failed or diversion drags over non electrified lines and pantograph down so would be unrealistic to have the pan up
Quote from: chrispearce on September 18, 2019, 06:29:07 AM
Quote from: railsquid on September 18, 2019, 06:16:09 AM
I'm not an electrical wizard or a railway professional (so may be completely wrong), but my amateur take is that theoretically it would be possible, but generator vans presumably only provide enough power for heating/lighting/cooking etc. in passenger accommodation. For enough juice to power a locomotive you'd basically need much of the innards of a diesel-electric loco (leaving aside the question of how you get the power to the electric loco other than tying the lead to the pantograph).
In real life, if a electric locomotive needs to be moved somewhere where there are no wires, you'd just put a diesel loco in front.
Thanks railsquid. That is helpful. Surely it must be possible to have a diesel generator that can be plugged into the loco to power it. I am sure those who preserve 3rd rail locos have done it.
The only operational 3rd rail loco I'm aware of (and again I might be wrong) is the Class 73, which has its own diesel generator on board (there's one in use on permanent way duty on the Gloucestershire/Warwickshire Railway).
Are you looking for a situation where the electric is away from the wires but still at the head of the train?
Usually as stated above the diesel drag the electric and rake when there are no wires, I have seen a few times where the electric is used as the cab car/DVT surrogate, but am not sure if it took two drivers one in the electric controlling the brake and one in the diesel applying power.
A late night service to New York used to have a diesel drag in the normal way except when it got close to NY they would shut the diesel down, raise the pan on the AEM7 and control the electric from the P42 (only a few P42s had the mod to enable controlling the electric, that was an interesting ride with the diesel making no noise yet still being able to lead the train), only other time I've seen this was when 31524 rescued 87014 but the ped blew its coolant and crapped out between stafford and crewe, they raised the pan on the 87 and we limped to Crewe where a red 86 replaced everything.
A generator van or Ethel is for train heating/lights and AC, they don't provide power throughput to an engine on the train.
Ic
I may have to 'bend reality' and 'invent' one in my laboratory. Rule 1 plus wonder technology may have to be the answer. :hmmm:
Your right there squiddy. The only thing i could think would be to have an on off switch on the loco roof to allow an electric loco to run pan up but that would look odd and silly without catenary
Ok. I get the impression that I could have a van behind the loco which contains a diesel generator which feeds power to the loco via a cable. The essence of the layout is a private/heritage railway where some o'head locos reside along with the more usual steam/diesel locos. I just wanted to see if it were reasonable to suggest that, although there was no catenary, the o'head locos still operated but did so by towing a generator van.
Quote from: chrispearce on September 18, 2019, 06:26:29 AM
Quote from: Bealman on September 18, 2019, 06:10:12 AM
You have a model locomotive that will only operate from overhead power?
I didn't know there was such a thing! :hmmm:
No I don't have such a loco. I do have a couple of locos with dummy pantographs but don't wish to install catenary. I was merely wondering if it were possible to create a 'generator van' to 'power' them.
Oh, ok, sorry, I misunderstood the question. Personally I'd just use Rule 1... in fact I've done it on my layout.
I've ran an electric loco with the pantographs up, and ignored the fact there's no wires. I was the only one seeing it, and guess what, it didn't bother me at all!
Quote from: Bealman on September 18, 2019, 07:02:00 AM
Quote from: chrispearce on September 18, 2019, 06:26:29 AM
Quote from: Bealman on September 18, 2019, 06:10:12 AM
You have a model locomotive that will only operate from overhead power?
I didn't know there was such a thing! :hmmm:
No I don't have such a loco. I do have a couple of locos with dummy pantographs but don't wish to install catenary. I was merely wondering if it were possible to create a 'generator van' to 'power' them.
Oh, ok, sorry, I misunderstood the question. Personally I'd just use Rule 1... in fact I've done it on my layout.
I've ran an electric loco with the pantographs up, and ignored the fact there's no wires. I was the only one seeing it, and guess what, it didn't bother me at all!
Thanks. That was my genuine sentiment but I'm glad to know you've done it.
You could always top and tail, electric one end-coaches-diesel on the other.
To look at that set up it would be feasible as it would be assumed the diesel provides power and the electric is just along for the ride.
Quote from: Intercity on September 18, 2019, 07:07:47 AM
You could always top and tail, electric one end-coaches-diesel on the other.
To look at that set up it would be feasible as it would be assumed the diesel provides power and the electric is just along for the ride.
A sensible idea. Thanks. BTW your 'location' is brilliant. Makes me giggle. Is Philly really a dirty place?
I've actually seen it done, but only with a little 0-4-0 loco, but only for moving it around the yard, the genny wasn't big enough for it to be towing things. The loco had batteries as well, but they weren't well...
As they say a genny big enough to power a loco for it's purpose would need a wagon as big as a diesel loco. so just put a diesel on..
I've heard of preserved trams running with a generator on a trailer, and a third rail loco/unit could probably do this too. But it's unlikely for a locomotive on the 25kV system, as the high voltage needs a lot of insulation and electrical clearances.
I do know of small European two car units by Stadler which have a short middle "module" with either diesel or overhead capability depending on usage. I'm not sure if those are field-swappable though.
https://en.wikipedia.org/wiki/Stadler_GTW#Propulsion (https://en.wikipedia.org/wiki/Stadler_GTW#Propulsion)
I'm not aware of any generator lash-ups that would provide traction power for a large electric loco, plus it would have to be pretty hefty connecting cable! Generally it's only control signals that are carried through I would have thought.
An electro-diesel such as the UK class 73 would be most appropriate of course.
I must admit that personally I don't like to see electric locos with pantos up on non-electrified layouts, so my fleet of electrics doesn't get to run on those parts of my layout. Electrification is planned for the future though :D
I've mainly run them with pantographs down, but of course, that wouldn't happen in reality either, so either way, I lose. ;)
I will never install even posts to simulate overhead.... I knock over enough telegraph poles as it is when I'm track cleaning!
Quote from: Bealman on September 18, 2019, 09:14:57 AMI will never install even posts to simulate overhead.... I knock over enough telegraph poles as it is when I'm track cleaning!
I like the Ratio telegraph poles - they are flexible so can withstand the odd knock.
Yeah, they're good. I went for the Kestrel ones back then because of the cost factor :worried:
Catenary poles - now you see them:
(https://live.staticflickr.com/65535/48721243593_5d013c89ca_z.jpg) (https://flic.kr/p/2hek7ig)
Roco ET85 (BR485/885) (https://flic.kr/p/2hek7ig) by Rail Squid (https://www.flickr.com/photos/railsquid/), on Flickr
Now you don't:
(https://live.staticflickr.com/65535/48696239286_0bf97a07d1_z.jpg) (https://flic.kr/p/2hc7Xow)
Minitrix G 4/5 H (5502) with miscellaneous coaches (https://flic.kr/p/2hc7Xow) by Rail Squid (https://www.flickr.com/photos/railsquid/), on Flickr
:D
Ok, removable ones....
In the words of Australian politician(?) Pauline Hanson,
"Please explain" :hmmm:
Quote from: Bealman on September 18, 2019, 10:46:46 AM
Ok, removable ones....
In the words of Australian politician(?) Pauline Hanson,
"Please explain" :hmmm:
Err, holes on either side of the track, hand of god comes down and removes/adds as desired, mainly removed for purposes of photographing kettles.
Not going to win me any prizes for realism, but whatever.
Well I don't see why not....
The vegetation disguises it well.
Or is that the low camera angle? :thumbsup:
Quote from: railsquid on September 18, 2019, 10:52:39 AM
Quote from: Bealman on September 18, 2019, 10:46:46 AM
Ok, removable ones....
In the words of Australian politician(?) Pauline Hanson,
"Please explain" :hmmm:
Err, holes on either side of the track, hand of god comes down and removes/adds as desired, mainly removed for purposes of photographing kettles.
Not going to win me any prizes for realism, but whatever.
Nowt wrong with that - I've done it myself with a few trees that are too tall to fit inside the layout transport casings, but would be too low to hide the track disappearing round to the fiddle yard if I made them small enough to fit the casings.
Are those poles flexible, Ian?
Cos I must admit I like the pics under the "cables!"
If you ran the generator from the train wheels the produced electricity could power the motor driving the train that powers the generator,mmmm i'll get onto it once ive finished defrosting my cold fussion machine.
Quote from: Bealman on September 18, 2019, 11:44:11 AM
Cos I must admit I like the pics under the "cables!"
Oh well, in that case I have loads of those :D
(https://www.ngaugeforum.co.uk/SMFN/gallery/79/5885-180719175641.jpeg)
(https://www.ngaugeforum.co.uk/SMFN/gallery/79/5885-240719155017.jpeg)
(https://www.ngaugeforum.co.uk/SMFN/gallery/77/5885-220519190437.jpeg)
Or something closer to 'home'......
https://www.ngaugeforum.co.uk/SMFN/index.php?topic=14741.msg533491#msg533491 (https://www.ngaugeforum.co.uk/SMFN/index.php?topic=14741.msg533491#msg533491)
I am driving myself mad, as this thread has kicked off a memory of reading about US diesel electric locos where they hook up a second loco that has no engine and no cab and its traction motors are supplied solely from the 1st loco. There is a specific name for the slave locos, but I can't remember it!
Ah, it's just clicked - they are "slugs."
These posts are brilliant. Thanks everyone. However, I am considering something that is a cross between a Flux Capacitor and a Viktor Schauberger vortex implosion perpetual motion generator and stick it in a baggage vehicle behind the loco. That should do the trick. :D
Some US heavy shunting combos were known as "Cow and calf" (https://www.american-rails.com/cow-calf.html (https://www.american-rails.com/cow-calf.html)). I think you can buy models of them from some US dealers and I saw some years ago in a Walthers N-scale catalogue.
One of the worst things you an do to an electric traction motor is to run it at high mechanical load and low speed. One way to get around this is to (effectively):
- take two heavy duty diesel-electric shunters
- couple them together more-or-less permanently
- remove the diesel motor and generator from one, and replace them with a big block of concrete for traction
- run the electric traction motors on both units from the diesel engine and generator on the still complete loco
There were also "slugs" which was a slightly different approach to the same problem.
Neil
According to https://en.m.wikipedia.org/wiki/Slug_(railroad) (https://en.m.wikipedia.org/wiki/Slug_(railroad)) some diesel-electrics can generate more power than they can use at low speeds (before wheel-slip sets in) and a slug is used to provide extra adhesion/traction, using that excess power.
The BR class 13 is effectively a cow-and-calf lash-up
(https://upload.wikimedia.org/wikipedia/commons/thumb/5/54/Class_13_no._13003%2C_permanently_coupled_Master-Slave_locomotives%2C_Tinsley_Marshalling_Yard%2C_Nigel_Tout%2C_6.8.74.jpg/1280px-Class_13_no._13003%2C_permanently_coupled_Master-Slave_locomotives%2C_Tinsley_Marshalling_Yard%2C_Nigel_Tout%2C_6.8.74.jpg)
https://en.wikipedia.org/wiki/British_Rail_Class_13 (https://en.wikipedia.org/wiki/British_Rail_Class_13)
Quote from: stevewalker on September 19, 2019, 11:18:38 AM
According to https://en.m.wikipedia.org/wiki/Slug_(railroad) (https://en.m.wikipedia.org/wiki/Slug_(railroad)) some diesel-electrics can generate more power than they can use at low speeds (before wheel-slip sets in) and a slug is used to provide extra adhesion/traction, using that excess power.
Looks like I was wrong on this. I'll delete my previous post.
But note that the electricity generated by the alternator attached to the engine and used by the traction motors will be somewhere in the hundreds of volts, so the connectors and cable feeding it across to the slug only have to tolerate that voltage. Feeding 25000V via a cable would be a very different matter. Some trains such as Pendolinos have a 25kV cable along the set at roof level, but this is permanently connected and can only be removed in the depot.
QuoteBut note that the electricity generated by the alternator attached to the engine and used by the traction motors will be somewhere in the hundreds of volts, so the connectors and cable feeding it across to the slug only have to tolerate that voltage. Feeding 25000V via a cable would be a very different matter.
At low voltage the current will be greater,so thicker conductors and less insulation will be needed compared to the same load run at a higher voltage were a more insulation will be required,but the conductors will be thinner.
Quote from: edwin_m on September 19, 2019, 05:00:07 PM
Quote from: stevewalker on September 19, 2019, 11:18:38 AM
According to https://en.m.wikipedia.org/wiki/Slug_(railroad) (https://en.m.wikipedia.org/wiki/Slug_(railroad)) some diesel-electrics can generate more power than they can use at low speeds (before wheel-slip sets in) and a slug is used to provide extra adhesion/traction, using that excess power.
Looks like I was wrong on this. I'll delete my previous post.
I only knew because I happened to read it a few months ago.