Span device of former Messina Powerline Span

[Alpha]

On http://www.grafoeditor.it/link1.pdf, page 14 the span device of former Messina Strait Powerline Span is described. It was placed at Torre Faro, Sicily and its building exist still today. Interesting is however, that for this span such a device was used. Under which condition a span device for a long distance powerline span would be sensitive or necessary? As I know no other long-distance powerline span use or used such a device.