Automatic new line are easy but it's harder to automatize old line without interrupting traffic. It has been done for line 1 in Paris between 2007 and 2011 (htt

Automatic new line are easy but it's harder to automatize old line without interrupting traffic. It has been done for line 1 in Paris between 2007 and 2011 (https://en.wikipedia.org/wiki/Paris_M%C3%A9tro_Line_1 https://en.wikipedia.org/wiki/Paris_M%C3%A9tro_Line_1) but all other old line in Paris have still not been automatized.