And traffic between geographically separated company networks can be routed through a virtual private network (VPN) tunnel instead of being exposed to the open Internet.

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Our correspondent says there will be serious question about how a major tunnel on one of Japan's most important traffic arteries could have failed so catastrophically, with the private company that runs the highway saying the tunnel had undergone a major inspection just two months ago and had been given a clean bill of health.

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Having watched losses soar on the Channel Tunnel project, the private sector is rightly wary of handling huge infrastructure projects on its own.

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Our Londoners' tube will have more and better trains, more lines and more services, whilst Prescott's Public Private Partnership remains stuck in the tunnel with signal failure.

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Mr Obama noted that the involvement of several jurisdictions, as well as private companies whose payments were tied to performance, meant "construction workers are on the job digging this tunnel, doing great jobs, getting good pay".

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