Wednesday, January 29, 2014

RN90 Project - road to nowhere?

Whether you make your way to Les Arcs by road or rail you will probably notice a great deal of heavy construction work going on just after Moutiers, as the RN 90 and the railway beside it begin their tortuous ascent through the narrowing Isère gorges to Aime, Bourg and eventually Val d'Isère at the head of the Haute Tarentaise valley. A reader emailed me to ask me if I knew what was going on there, so here goes:

Image of the new road, note old road on the right

The 46 million euro scheme is called the Deviation de la RN90 á Montgalgan, and involves diverting the road to the other side of the  Isère river, below the site of the now disused Loyettaz Quarry, over a distance of 1.75km. A second viaduct will take it back to its original trace at St Marcel, just before the Tunnel de Siaix. It's a massive project that's going to take 4 years to complete. The end result will be a four-lane dual-carriageway and the widening of the bed of the Isère river to 18m (now 12m) by scrapping part of the 'old' road.  The old quarry, which really is a scar on the landscape, will be 'naturalised' and re-planted with indigenous forest trees that were destroyed in 1898 with the rush for industrialisation in the Tarentaise valley.   Rubbish and pollutants will be removed from the bed of the Isère to encourage it back to its natural state, and by making it wider possible future flooding will be avoided (remember global warming?).

JCB buried by falling rocks in April 2013
All this ecological virtue is fine, but it's hardly the main reason for undertaking such a huge scheme. What's really behind it are increasing problems of rock falls and landslides onto the road from the geologically-unstable Montgalgan cliff, visible in the top right of the picture above. At the start of the project there was a huge eboulement that effectively buried a large JCB excavator, thankfully without any casualties. Anyone who uses the RN90 as regularly as I do will be used to seeing piles of rock at the side of the road, and while stuck in the  frequent Saturday traffic jams find plenty of time to admire the complex spider-web of netting, ropes and fences erected over the years to protect the railway and road.

Viaduct de Centron during construction in 2005
The RN90 carries up to 45,000 vehicles on a typical busy Saturday during the winter school holidays Many of the world's most famous and popular ski resorts are served by this road, and apart from the railway there's no other way into the valley.  In 2005 a similar project was undertaken at Centron, a few kilometres up the valley, with the construction of the imposing viaduct at the end the other end of Siaix Tunnel sweeping the RN90 to the right bank for exactly the same reasons as the Montgalgan project.

The new road is going to give a better view of the rambling 'Metaux Speciaux' works at St Marcel, where chlorine, vandium and various nasty-sounding 'alkaline metals' are made for the nuclear power industry. The plant takes full advantage of the adjacent railway line, dispatching its products in huge rail-tankers during the passenger-free hours of the night. Many of these large industrial complexes were established in the early 20th Century in order to take advantage of the possibilities of hydro-electric produce the huge amount of energy required to turn rocks into gas. Metaux Speciaux managed to produce so much electricity from its own hydro-power plants that for a time the excess was used the power the Lyon city trams!

But is the Deviation de la RN90 á Montgalgan all a huge waste of time and money? Certainly the environmental pressure group Vivre en Tarentaise think so.  From the congested 2-lane giratory system around Moutiers one will be able to speed toward the inevitable traffic jam that will occur when the wonderful new stretch of road funnels into one lane in the Tunnel de Saix, before joining the next embouteillage as the two lanes of the Centron viaduct converge at the tricky corner above the narrow Gorge de Centron. And then it's solid all the way to Bourg St Maurice and beyond....

Vivre en Tarentaise raises the question again of why not spend this money on the railway instead? The official answer is the the hundred-year old railway is already 'saturated' at peak times, with  no more space for any more trains. Most of it is single track and in tunnels.  Deep inside the mountain adjacent the Montgalgan scheme is the extraordinary  railway 'boucle', a long spiral tunnel by which the line rises from 480 à 520 m over a short distance. Like the deviation, it took 4 years to build in 1913.  
Boris enjoying the London cable car
Perhaps engineers and politicians today should try and emulate the ingenuity and determination of those earlier road and rail builders - if expanding the road or railway isn't going provide a solution to the problem of access why not look for a more radical solution? 60 years ago a massive telepherique was built to ferry concrete from railway trucks arriving at Bourg St Maurice station 23km up the valley to site of the Tignes hydro-electric dam at the Lac de Chevril (you can still see the footing of one of the pylons by the allotments in the park next to the funicular). Cable transport is taking off round the world as a cheap, safe way of moving people - there's even now a cable car across the Thames in London. So why not a huge cable car system with stops at all the main resorts/towns from Moutiers to Val D'Isere to transport people and their luggage silently up the valley. Just think of the view and how much CO2 could be saved.... something to dream about while stuck in those inevitable traffic jams of the future.

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