2005 London - Brighton speed run

Shot from the driver's cab, I found out a few things about the physical characteristics of this line, for instance that the signals are on the center or left side of the track. Feather signals much in evidence, including some indicating as many as four differents routes. All the ones in this video were black, but you could tell them by their unusual shape. The illustration below is overkill on various feather signals.
This is third rail territory, sort of unusual for high speed rail, I believe. We saw quite a few trains, all MUs.
I found this while perusing the Friends of the Rail forums. I looked at an article about GE diesels going to Australia, which led to EMD locos, and Caterpillar, where I found this speed run among other railway videos. I couldn't find it there again, so youtubed it to get the link. Top speed 100mph.
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The Brighton line was electrified in the 1930s as a remedy for mass unemployment. But the need was for reliable trains for a very busy commuter route. The trains are always very busy to London Victoria. There is very little freight.