Because of technical and architectural considerations, a unique combination of rolled and cast steel was selected for the arch bridge as well as for certain supports elsewhere along the viaduct.

由于技术和建筑学的考虑，一种独特的轧制钢被选用于拱桥和高架桥身的某些特定支撑。

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Disused since 1986, the 170-arch viaduct defied engineers' fears about its condition, says Mr Noble.

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The route runs over the 33-arch Hockley Viaduct alongside the M3 at Winchester.

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Work to extend the line began last year and if fundraising goes to plan it should be completed in 2010, with steam trains entering East Grinstead over the 10-arch Imberhorne viaduct.

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