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Nancy "tram" now withdrawn
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AlbertBeale
Established Member
Doesn't Padua have something similar?
dutchflyer
Established Member
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Nancy itself-before they got talked into this new way constructed a classic trolleybussystem before-when many french towns were building trams. So its back to what it was! CAEN in Normandie choose also for this system and has changed it into a proper tramway a few years ago.
Another mostly french phenomenon-also from those years, are the tiny non-driver metro´s named as VAL- Lille, Toulouse, Rennes have these. But these function quite well- perhaps problems may arise when they are also due for renovation etc-too few customers, lack of spares etc. Typical tram-promoters state that they should have built a proper tramway. No idea what is more cost-effective, as of course drivers/staff wages and right now even the availability of enough staff will have biggest influence on that.
Another mostly french phenomenon-also from those years, are the tiny non-driver metro´s named as VAL- Lille, Toulouse, Rennes have these. But these function quite well- perhaps problems may arise when they are also due for renovation etc-too few customers, lack of spares etc. Typical tram-promoters state that they should have built a proper tramway. No idea what is more cost-effective, as of course drivers/staff wages and right now even the availability of enough staff will have biggest influence on that.
Vespa
Established Member
The problem with guided buses is manufacter dependency as there is too few companies that will make them increasing running cost and expensive spare parts with renewal of life expired stocks, you will trapped in a disadvantagious commercial arrangement.
Guided buses is the worst of all worlds.
I have ridden on one from Venice to the mainland, the ride quality is awful with constant rocking that it can make some feel seasick, the tyres needs to replaced at regular intervalswhich is non standard, the road develop tyre indentions that needs to be leveled, it's very slow.
Classic trams have several established manufacturers, proven technology, higher speed, greater competition and cheaper replacements, interoperatabilty between tram systems inuding tramtrains, its a no brainer.
edwin_m
Veteran Member
This is the Translohr system, similar but incompatible, and with most of the same disadvantages. However, it is considerably more common. I think Bombardier gave up on TVR after Nancy and Caen but Lohr persisted with their system.
The major difference is the Translohr system can't be used away from the guidance rail, which you would think was more of a disadvantage over Bombardier's system. I don't understand why Paris has built a couple of those, whilst at the same time building normal tramways: they really can't be that much cheaper than normal trams, and must cost more to run
edwin_m
Veteran Member
Using TVR off the guiderail was also questionable - there was at least one incident where part of the vehicle swerved unexpectedly at the transition to/from the guided section, striking an OLE pole. It also means double-wire overhead is needed, whereas Caen only had one wire with return through the rail.
I had a ride on one of the Paris Translohr routes, which was considerably inferior to a tram, feeling very cramped with the large boxes over the road wheels. The only advantage I can see is the turning radius, where one of the curves looks to be about 15m and trams typically don't go below 25m. Having said that, trams can be designed for 15m if really necessary (Nottingham goes down to 18m and Berlin to 14m).
The Paris routes have a concrete slab over the area the rubber tyres pass over, which avoids the problems of rutting of an asphalt surface seen on the Nancy video but introduces most of the construction cost and utility diversions needed for a tramway. For the same capacity and therefore similar weight, a rubber tyre system is also likely to use a lot more energy.
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It's not Lohr property anymore. They wanted to abandon it, but the French government twisted Alstom's arm into taking it over, and to help, twisted RATP's arm into ordering it.
Fleetmaster
Member
The YouTube video omits one pretty obvious problem with their reasoning.
These vehicles are huge. Replacing them like for like with trolleybuses surely means you need at least three trolleybuses for every tram.
That surely materially affects any claim that begins with the idea these are just trolleybuses with occasional use of guide rails, so why not just use trolleybuses?
The fact they take up less road space as they turn in the congested areas where guidance is used, also then becomes a factor since they are only occupying these busy junctions for a third less time than the equivalent trolleybus route.
I can't see why they're not more popular as a cheaper alternative to trams that can also tackle steeper gradients and even be driven entirely independently away from the wires.
Obviously you go with a tram if you can afford it, but in a world looking for quick and cheap ways to decarbonise cities, it seems perverse to overlook this system for an obviously flawed reason.
These vehicles are huge. Replacing them like for like with trolleybuses surely means you need at least three trolleybuses for every tram.
That surely materially affects any claim that begins with the idea these are just trolleybuses with occasional use of guide rails, so why not just use trolleybuses?
The fact they take up less road space as they turn in the congested areas where guidance is used, also then becomes a factor since they are only occupying these busy junctions for a third less time than the equivalent trolleybus route.
I can't see why they're not more popular as a cheaper alternative to trams that can also tackle steeper gradients and even be driven entirely independently away from the wires.
Obviously you go with a tram if you can afford it, but in a world looking for quick and cheap ways to decarbonise cities, it seems perverse to overlook this system for an obviously flawed reason.
edwin_m
Veteran Member
If the vehicles are able to run unguided on the public road, then an unguided trolleybus of the same size could do just the same if there was a need to. Or perhaps junction congestion isn't an issue on this route, and a smaller vehicle running more often is more appropriate to the passenger numbers?
The video mentioned that width of swept path is one of the few advantages of this technology, and that they would have to make the path wider on the sections which had guiderails, to allow unguided trolleybuses to run instead. Clearly, on this route at least, that is possible.
I already posted about the extra energy consumption of these vehicles compared with a tram of similar size, and the accidents that have taken place in the transition between guided and unguided mode. On the guided sections you still need a concrete slab and utility diversions, only one rail but two overhead wires, so it's unlikely to be much cheaper than a tramway.
The supplier walked away from this technology over a decade ago, which they wouldn't have done if they saw any opportunity to make any money out of it. The only other system (in Caen) was replaced by a conventional tramway. Nothing really to see here other than yet another niche gadgetbahn.
Fleetmaster
Member
I had assumed their depot run is done via a permissible route only.
it seems pretty clear from the video that their tight urban turns are in classic tram territory, in terms of the general busyness of pedestrian, cycle and motor traffic. I definitely think this system was chosen because they couldn't afford a tram and it couldn't do the gradient even if they could.
Possible, sure. Desirable? If their hands are tied and it has to be replaced, you obviously rip up and relocate whatever you need to change to keep the people moving. Whether they do keep moving if you need three trolleybuses for every tram is clearly an issue, not just in the busy areas but in the termini and depot.
The point being, they can't use trams here because of the gradient (as well as the fact you can hardly reap the operating savings of a tram if you can't afford to install it in the first place).
You only mentioned one? You can typically chalk that up to operator error.
Depends how much guidance is used. The video seems to imply very long sections of unguided running in the outer areas, which seems logical.
Perhaps. I was merely irked by what seems to be a very big oversight in the argument that they're just trolleybuses, so just replace it with trolleybuses.
edwin_m
Veteran Member
I had assumed their depot run is done via a permissible route only.
Quite possibly, but a similar sized vehicle without guidance would probably also be restricted to certain permissible routes.
When they selected it, they probably thought they were getting something equivalent to a tram but cheaper. It's highly unlikely they actually did, when considering lifetime costs and the fact they were locked into a single supplier - who has now decided to abandon the product line.
Quite possibly, but a similar sized vehicle without guidance would probably also be restricted to certain permissible routes.
They clearly believe they can make an unguided trolleybus work in those areas, at the cost of widening the corridor slightly. The vehicle has exposed wheels, which make it more dangerous than a tram in pedestrian areas.
When they selected it, they probably thought they were getting something equivalent to a tram but cheaper. It's highly unlikely they actually did, when considering lifetime costs and the fact they were locked into a single supplier - who has now decided to abandon the product line.
It appears they have the option of replacing by normal trolleybuses or by bi-articulated trolleybuses of similar size to the GLT vehicles (these do exist elsewhere). So they have a solution if more smaller vehicles would be a problem for them.
Found a more detailed but rather dated article which says a little more about at least two accidents (the rest of it is worth a read too): https://www.lightrailnow.org/features/f_ncy001.htm
There's also this (translation from German of a citation from the Wikipedia page): https://www.urban-transport-magazine.com/die-neue-tram-nancy-bereitet-sich-vor/
But if they can run on long sections of unguided running, and the authorities evidently believe that the guided section doesn't really need guidance, then surely a straightforward unguided trolleybus could do the job without the downsides?
Fleetmaster
Member
If there is an inherent design flaw in the guidance mechanism, then yes, it's a bust.
The fact remains, if it did work as designed, a guided trolleybus offers distinct advantages over trolleybuses and trams for all the reasons previously said, and even articulated trolleybuses too.
It all comes down to this critical ability to have tram like features in the confined urban areas and transport hubs, without the expense and indeed inflexibility of a full tram network as it ranges out to the suburbs, up hill and down dale.
Not every city will have these needs, but with it being a rather obvious fact of life that cities are only getting busier, and planners being more and more conscious of the need to keep things moving and make the best use of the space available, the market will exist.
I can see these even being used in London, as mad as it might sound. There is a dire need for clean and efficient people movers that can range far and wide in a single route. Putting wires along these main drags is no issue. Laying tram tracks and tram stops is. There is the poltical will to give priority to tram like vehicles on busy London streets where it isn't necessarily there for mere buses.
There is a clear need for precision and predictability of movement in the core central areas, which will in due course become largely a mixed use car free zone whatever else happens, so the laying of concrete and guide rails as part of a transformative but evolutionary change will be less of a jolt.
A core network supporting a more flexible battery electric bus network, where interchange between modes would be ridiculously easy, almost as easy as switching between buses.
The fact remains, if it did work as designed, a guided trolleybus offers distinct advantages over trolleybuses and trams for all the reasons previously said, and even articulated trolleybuses too.
It all comes down to this critical ability to have tram like features in the confined urban areas and transport hubs, without the expense and indeed inflexibility of a full tram network as it ranges out to the suburbs, up hill and down dale.
Not every city will have these needs, but with it being a rather obvious fact of life that cities are only getting busier, and planners being more and more conscious of the need to keep things moving and make the best use of the space available, the market will exist.
I can see these even being used in London, as mad as it might sound. There is a dire need for clean and efficient people movers that can range far and wide in a single route. Putting wires along these main drags is no issue. Laying tram tracks and tram stops is. There is the poltical will to give priority to tram like vehicles on busy London streets where it isn't necessarily there for mere buses.
There is a clear need for precision and predictability of movement in the core central areas, which will in due course become largely a mixed use car free zone whatever else happens, so the laying of concrete and guide rails as part of a transformative but evolutionary change will be less of a jolt.
A core network supporting a more flexible battery electric bus network, where interchange between modes would be ridiculously easy, almost as easy as switching between buses.
edwin_m
Veteran Member
There was also a system that followed buried wires in the road, based on the one used for the Channel Tunnel service tunnel, and one that followed a trail of embedded magnets. Along with the optical system, these share the problem that they rely on an active system to steer the vehicle, so it would instantly lose guidance if that system failed, and any skidding on wet/icy surface could also take the vehicle off its intended path. The TVR and Translohr do have mechanical guidance so shouldn't suffer from these problems, but the force that keeps the guidewheel on the rail is much less than that on a tramway wheel, which would make it more prone to loss of guidance if there was some obstruction in the rail grooves (maybe even packed snow).
The only guidance system that is remotely successful is the kerb guidance found in Leeds, Ipswich, Dunstable and Cambridgeshire. This is a simple all-mechanical technology that can readily be fitted to standard buses, but has the problem that there must be a gap in the guidance, imposing a speed restriction, everywhere other vehicles or pedestrians (including wheelchair users) need to cross it.
The only guidance system that is remotely successful is the kerb guidance found in Leeds, Ipswich, Dunstable and Cambridgeshire. This is a simple all-mechanical technology that can readily be fitted to standard buses, but has the problem that there must be a gap in the guidance, imposing a speed restriction, everywhere other vehicles or pedestrians (including wheelchair users) need to cross it.
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