Why does London put barriers on the rails?

for protection and awareness

Explanation:

Hampstead

The deepest station is Hampstead on the Northern line, which runs down to 58.5 metres. 15. In Central London the deepest station below street level is also the Northern line. It is the DLR concourse at Bank, which is 41.4 metres below.

these the citzens and goverment come to terms some of the amendments gave the states more power then the goverment and some protocted americans rights