What's quite interesting about airport/aviation security is that the additional measures brought in - don't seem to apply to other sectors.
Eg
Liquids - failed plot = ban on liquids
Underwear bomber - failed plot = 3D scanners
Shoe bomber - failed plot = take off shoes
yet
Rucksack bombs on tube, bus and Madrid train - (52 dead London, 191 dead Madrid) - but no scanners, sniffers or ban on rucksacks were brought in??
(happy to be corrected if there are indeed airport-style security gates in Spanish train stations).