Funicular railway power question

Last year we rode a funicular railway with a single overhead wire and a lar ge bank of resistors on the roof that got very hot when it was descending. I'm guessing that it was a DC motor/generator setup with the resistors abso rbing the generators output on the way down.
Today we rode a train with two overhead wires but no resistor banks. This t rain apparently runs on a three phase supply. Presumably the rails supplied the third "leg" of the supply but how safe is this with AC? Wouldn't the r ails be dangerously live relative to earth?
There were no warning signs and the track was unprotected so it must be saf e but I don't understand how. Can anyone explain? Also, how did the brakin g work?
https://en.m.wikipedia.org/wiki/Petit_train_de_la_Rhune
Tim
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On 06/07/2019 20:55, Tim+ wrote:

Why would they be? If the rails were earthed...
a three phase supply doesnt have to have each limb symmetrical with respect to earth.
Consider a star or delta transformer with one phase earthed.

Feeding overvoltage back into a low impedance supply.

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On 06/07/2019 21:08, The Natural Philosopher wrote:

I just spent ten minutes trying to check you out - and failed. I can't find anything saying that in either English or French.
One of the few other such systems is the Jungfraubahn, which I went on a couple of years ago. I'm damn sure there isn't a live rail - I walked across the track - so your guess must be correct.
Or you have a source I couldn't find!
Andy
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It was done on large three phase motors on radars which tended to have to be tested with covers off, and it was most certainly earthed on one rail. Brian
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On 06/07/2019 21:53, Vir Campestris wrote:

???
https://www.electronics-tutorials.ws/transformer/three-phase-transformer.html

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If you have ever played with slot racing cars the breaking when you bring up the plunger is done by shorting out the track. Brian
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You should be able to have anything earthed if you use a transformer for the supply with a separate secondary. Brian
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Tim+ expressed precisely :

It could have been single phase and neutral on the wires, or two phases and an earth via the earthed rail.
The motor would likely be synchronous, driving a worm gear. The drive would only allow the car to decend limited by the motor's speed.
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On 06/07/2019 23:24, Harry Bloomfield wrote:

It is three phase and the rail is one phase and is earthed.
Phases are only phased with respect to each other, they dont care about their relationship with 'earth'.
Voltage is not absolute, It is relative, as any bird sitting on a 132KV line can tell you

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The Natural Philosopher has brought this to us :

I see how that would work now. I had in mind star, with the centre point grounded - a delta output transformer with one point to ground would do it.
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Oh well,I’m glad someone does. ;-) Our physics classes never progressed to three phase power when I was at school and I’ve never had a need to understand it in any depth (or at all really) since then.
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On 07/07/2019 15:46, Tim+ wrote:

Blimey.
I sort of thought that anyone in a DIY group would have basic electrical knowledge

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On 07/07/2019 15:50, The Natural Philosopher wrote:

The only one I have ever actually worked on was at my mate's small business. Unless you have three phase at home for a lathe I'd have thought even fairly experienced DIY people wouldn't come across them.
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Yeah, but then you’re forgetting that TNP has to throw out gratuitous patronising comments regularly.
Tim
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On 07/07/2019 18:15, Tim+ wrote:

Three phase power is discussed here pretty often.
Indeed I believe you yourself brought it up in this thread
I told you how it probably was set up, you complained you didnt understand, I pointed you to a web page that explained it.
Whatr is patronsioing about that?
It was only someome moaning that tehy couldnt ne expected to undersatdn or summat that irritated me. I study shit I dont understand every day. Do it yourself!

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You call it “basic” but it’s knowledge needed by 0.01% of the population I would hazard. I guess the education system I went though didn’t see it as important.
Of course I could spend time reading up on it but without any need to understand it it any depth at all, I prefer to do other things with my time.
Hands up every DIYer here who dabbles with three phase power?
Tim
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Please Sir, I've got a 1hp variable frequency three phase inverter for a lathe motor. I had to think hard about the connections.
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Snip

My house is supplied with 3 phase.
Outbuildings and workshop equipment mostly use 3 phase. One day I'll get round to converting my centre lathe back to 3ph so I can use the reversing switch!

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I think you mean a rack Railway using cogs on a toothed Rail between the running rails.
Funiculars are rope hauled and purists reckon there must be an up and down cabin/carwith one counter balancing the other either by using water filled at the top or a motor to overcome any weight difference, even so the term as spread to other types but they all have a rope permanently attached to the vehicle which differentiates them from cable trams like in San Francisco where they can be released by a grip mechanism.
As for the 3 phase electrification there are not many examples left of this style which was a way of using AC at the beginning of the 20th century when motor technology was in its in infancy and speed control crudely done by pole changing, it also allowed for easy regeneration by using the motors as generators and feeding back into the supply. Frequencies were low as again motor technology was not advanced enough at the time for higher. The biggest user of the system was Italy where the 3600volt 16.7 Hz system remained in use on a good proportion of the network till the mid 1970’s. Junctions were very complicated as the two overhead wires had to have long insulated sections over pointwork and to cope with that the locomotives had a strange look due to the collector arms reaching out or extremities to cope with crossing the neutral sections.
https://images.app.goo.gl/3BhWnAr9suGyEfvE6
In that photo there is a water supply as used to top up steam locos, except here it was also used to top up the electrics as to get additional speed control liquid rheostats were used ,the liquid solution in those got got hot so was cooled by a secondary water circuit and radiators which had to be topped up at intervals.
At one time the system was almost adopted by the Metropolitan Railway in London to replace the original steam traction as electrical expertise for such things existed in Eastern Europe with the Ganz company of Budapest and not here at that time and their tender had been accepted. Only the arrival of American finance on other parts of what would become the London Underground network and the board of trade arbitrating in favour of the others whose American financier prefered the DC live rail system he knew from Chicago stopped the contract.
GH
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wrote:

Counterbalanced cars connected by cables, actually.

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