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Author Topic: Trams are ... Nice! And wireless.  (Read 503 times)
stuving
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« on: October 06, 2019, 08:04:58 pm »

Trams were rather popular when we had them recently. They were old ones, and here's a pretty new one. Before I comment on it, I'm sure there's some who would like a chance to identify where it is.
« Last Edit: October 06, 2019, 09:53:46 pm by stuving » Logged
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« Reply #1 on: October 06, 2019, 08:41:11 pm »

Nice! to see no overhead wires, charging strips in the road?
« Last Edit: October 06, 2019, 09:41:14 pm by MVR S&T » Logged
TonyK
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« Reply #2 on: October 06, 2019, 08:56:31 pm »

My first thought was Bordeaux, but I'm sure they aren't that colour. I shall go for Nice instead. I know they have finished / almost finished an extension.
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johnneyw
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« Reply #3 on: October 06, 2019, 09:10:39 pm »

I concur with Nice, also I found an online pic of said tramway with identical looks. Is this one of those where they ripped up the original "innovative bus based solution" because it wasn't?
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TonyK
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« Reply #4 on: October 06, 2019, 09:21:18 pm »

I concur with Nice, also I found an online pic of said tramway with identical looks. Is this one of those where they ripped up the original "innovative bus based solution" because it wasn't?

I think that may have been a part of the background, in that bus lanes were tried but didn't help much.

I have since read that  the trams run under OHLE for much of the route, with on-board battery power for the historic parts where lines simply would not look French enough. It proved a cheaper option than the Bordeaux method.
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stuving
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« Reply #5 on: October 06, 2019, 09:48:29 pm »

I concur with Nice, also I found an online pic of said tramway with identical looks. Is this one of those where they ripped up the original "innovative bus based solution" because it wasn't?

I think that may have been a part of the background, in that bus lanes were tried but didn't help much.

I have since read that  the trams run under OHLE for much of the route, with on-board battery power for the historic parts where lines simply would not look French enough. It proved a cheaper option than the Bordeaux method.

It is indeed Nice line 2 - still being built now. And look mum - no wires!

The usual story about wireless trams is that they are for historic city centres that would be visually marred by all the string. But this is hardly the historic centre; Magnan is a suburban crossroads about halfway to the airport. Line 2 uses new trams (though the differences are not that noticeable to passengers), and those metal strips in the road are Alstom's new ground pick-up systems - SRS. Their first go at this - APA, as used in Bordeaux - was a continuous feed, divided into short sections that are energised only when there's a tram on top.

Most of Line 1 (open in 2007) has wires; there are just two gaps for the two bigger squares (Masséna and Garribaldi), each just one stop long. These are dealt with by biggish NiMH batteries, though usually they are traversed at very low speed because of the number of people wandering around close by. For Line 2, all traction power on the  open-air sections comes via those SRS strips at each stop in just 20s, and is stored in supercapacitors rather than batteries. But that's all outside the centre - there is (or will be) a 3 km tunnel right under the city to the port, where the terminus will be on the quayside. There are certainly some wires inside that tunnelled section, and perhaps the full length.
« Last Edit: October 06, 2019, 09:54:46 pm by stuving » Logged
stuving
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« Reply #6 on: October 06, 2019, 11:00:34 pm »

I concur with Nice, also I found an online pic of said tramway with identical looks. Is this one of those where they ripped up the original "innovative bus based solution" because it wasn't?

I think that may have been a part of the background, in that bus lanes were tried but didn't help much.

Sort of. There were trunk bus routes that ran east-west (but mainly west) along the route of the new line 2 trams, then turned off up a variety of valleys. Now the surface part of line 2 is operating, these have been rejigged to deliver passengers to the trams. As part of a complete reworking of the bus system, some of the trunk buses (lignes fortes) have been replaced by lignes a effet tram, promising 8 minute intervals. So lines 3 and 22, serving Le Madeleine and Croix de Berra from Magnan and running into the city from there, have been linked at Magnan into a U-shaped new line 6. In the city, these new lines are getting the "busway" treatment - segregated lanes with a raised edge - some along new routeings. 

The effect of all this delivering passengers to the trams as primary radial carrier is entirely predictable - overcrowded trams.
« Last Edit: October 06, 2019, 11:10:07 pm by stuving » Logged
stuving
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« Reply #7 on: October 08, 2019, 12:09:08 am »

Here's a few more points about Nice and the question "wireless trams - why?" 

While the selling point for ground pick-up is preserving the visual amenity of historic city centres, in Nice it's used on suburban runs and in a couple of not-that-historic squares. The trams don't go into old Nice - the streets are too small - they just run along the edge. And as to saving the Place Masséna having masts to hold up its wires, picture 1 of where the wires run out shows it's got posts anyway. They are being squatted by some dubious-looking glowing multi-coloured plastic sculptures - Jaume Plensa's Conversation à Nice - put up in 2007, coincidentally when the trams arrived. Picture 2 shows the trams, and friends, in the square.

There was meant to be some kind of rebelliousness at Masséna that day, involving lycéens, or so it said in Nice-Matin. I wasn't there at exactly the time given, but within 30 minutes before and after, and saw nothing. Maybe the French state's precautions against such revolutions (picture 3) were very effective ... or something.

Also here's a couple of links I forgot to add, on the line 2 trams, and Alstom's descriptions of their APS and SRS.
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stuving
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« Reply #8 on: October 08, 2019, 12:17:19 am »

And one more picture, which was on the wall in the flat I stayed in - Place Masséna again. showing the original Nice trams.

While Alstom talk about their ground pick-up idea being inspired by third rail trains, and claimed it as a first in Bordeaux, if you look at the pictures of Nice's old trams (Compagnie des Tramways de Nice et du Littoral) you will see that the city ones were all ground pick-up. This is the "slot racer" method, similar to what was used in London for some routes up to closure, and to start with in other places that then gave it up as too unreliable or dangerous. The same company also ran along the coast (presumably using the same trams) from Cagnes-sur-Mer to Monaco, about 25 km, and to some villages inland, using overhead wires.

To add a little more coincidence to this, one of the earliest lines in Nice - up the hill to Cimiez - was originally powered by accumulators because of its steepness. At that date (1895) the alternative (for which it was too steep) was horses. It was rebuilt with overhead wires when Nice's other lines were electrified, and also changed from 60 cm to metre gauge - which was odd as the other lines were wider gauge (1.44 m, according to the on-line version).

Nothing new, is there?
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broadgage
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« Reply #9 on: October 08, 2019, 12:09:33 pm »

I would be very doubtful about any form of low level electric pick-up for street running trams. Anything recessed below ground level will be vulnerable to water or debris ingress.
Any means to render the supply equipment safe except when a tram is over it, adds cost and complexity and the risks of a failure.

The future is IMHO overhead electrification at the relatively low, though still dangerous, voltage of 550 to 750 volts. Limited battery operation for short sections that cant be readily electrified is worthwhile.

Another factor to be considered is rendering the electrification a bit less conspicuous. The Croydon tram scheme must be one of the worst in this respect.
In particular, more use needs to be made of the tramway supports for other purposes.
Street lighting equipment.
Traffic signals.
CCTV cameras.
Road signs and notices.
Hanging flower baskets.
Festive illuminations.
Waiting shelters for passengers.

Should ALL be attached to the supports for the tram wires, wherever possible, rather than erecting additional posts.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
TonyK
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« Reply #10 on: October 08, 2019, 09:08:12 pm »

While Alstom talk about their ground pick-up idea being inspired by third rail trains, and claimed it as a first in Bordeaux, if you look at the pictures of Nice's old trams (Compagnie des Tramways de Nice et du Littoral) you will see that the city ones were all ground pick-up. This is the "slot racer" method, similar to what was used in London for some routes up to closure, and to start with in other places that then gave it up as too unreliable or dangerous.

The "Scalextric" slot in the middle was the first method used on the Blackpool tramway. It had a very short lifespan, as it was constantly filling with sand and sea water. OHLE meant that the trams could at last run in bad weather. They may have gone with the last refurb, but into this century, there were plenty of places on the paved promenade route where you could see where you could see where the slot had been filled in. But surely this is something different, maybe induction coils rather than direct contact?


In particular, more use needs to be made of the tramway supports for other purposes.
Street lighting equipment.
Traffic signals.
CCTV cameras.
Road signs and notices.
Hanging flower baskets.
Festive illuminations.
Waiting shelters for passengers.

Should ALL be attached to the supports for the tram wires, wherever possible, rather than erecting additional posts.

The general method with modern tramways seems to be to emphasise that it is a separate entity by keeping the permanent way uncluttered by anything that isn't required for the operation of the trams. There may be lights co-located in a few places - I think the plan for the Blackpool extension to North Station is to use four pairs of posts that were used when trams last went that way 80 years ago. They have grown lamps, which I believe will stay.
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mjones
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« Reply #11 on: October 08, 2019, 09:56:41 pm »

Tony: "But surely this is something different, maybe induction coils rather than direct contact?"

It is still direct contact, but on an embedded rail that protrudes slightly above the road surface rather than a slot. A current collector shoe projects  below the tram to  slide along the conductor rail.  To avoid having exposed conductors in the middle of the road the rail is made in sections that are insulated from their neighbours, and the power is switched electronically so that the rail is only live when the tram is above it. Alstom are developing their system for potential use on road vehicles- this requires two conductor rails, as there are no tracks for the neutral connection,  and a steerable collector arm to keep the shoe aligned with the rail.
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stuving
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« Reply #12 on: October 08, 2019, 11:26:32 pm »

The "Scalextric" slot in the middle was the first method used on the Blackpool tramway. It had a very short lifespan, as it was constantly filling with sand and sea water. OHLE meant that the trams could at last run in bad weather. They may have gone with the last refurb, but into this century, there were plenty of places on the paved promenade route where you could see where you could see where the slot had been filled in. But surely this is something different, maybe induction coils rather than direct contact?

I'm not sure whether that question was about the new systems or the old ones! Conduit systems were quite common right through trams' lifetime, mainly in the centre of large cities where people think their buildings (and themselves) are special and can afford the cost. It was much more expensive to build and maintain. The design of the system used in Blackpool is attributed to Michael Holroyd Smith, who built the whole thing, and he also designed the overhead equipment when that seemed a better idea.

The main conduit systems were all pretty similar - two conductor rails with a plough between them (dangling from a the tram) and sprung bushes on each side. That means there was no current return through the rails. There were also ground contact systems, and in this case they differed a lot in their patented details. The basic idea was to have studs in the road, slightly raised, and a long contact-cum-magnet that slides over them. The magnet operates a switch under the stud to make it live, and - in theory - once it moves on the switch drops out.

Mechanical switches in holes in the road have a habit of getting stuck, due to the ingress of crud, so - after complaints about the dead horses - they put a contact at each end of the tram that was earthed via its body and wheels. Provided each stud's feed has a fuse, if it sticks it get disconnected, and if two are under the contact skate at any time, trams need not get stuck.

These were tried in Paris, Hastings, Torquay, Lincoln, and London ... but didn't last long. Now why would that be? Obviously this is almost the same as Alstom's APA, give or take the available technology of the day.
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broadgage
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« Reply #13 on: October 09, 2019, 06:47:31 pm »

Regarding the stud contact system in the preceding post, there was indeed some risk that a stud could remain live after the tram had passed.
Some trams were fitted with an additional collector that detected any still live stud. Rather than short circuiting it, a warning bell on the tram sounded. The driver was then to stop the tram and affix a moulded rubber cover over the live stud, to reduce the risks of accidents to horses and people.

Sounds fraught with hazards and the system found little favour.

As an aside, I advise against stepping on tram rails with bare feet. They are often live at a very low and usually harmless voltage, caused by voltage drop along the rails.
Under fault or failure conditions, or if the victim is unusually vulnerable, there is a tiny but real risk of fatal accident.

All but very short tram systems employ "negative boosters" the purpose of which is to "suck" return current out of the running rails and force it into an insulated return conductor.
Traditionally this was achieved by a motor generator set, these days a solid state device is probably used.
Any failure of the negative booster could leave a dangerous voltage on the running rails, hopefully only briefly, but very unfortunate if someone had one bare foot on the rail and the other in a puddle.
The risk is greatest in a seaside resort where persons intending to bathe in the sea might well go un-shod to the beach.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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