A very interesting point in the link. In resume yes, it seems that trains really would physically fit in the tunnels and would enter and exit the tunnels withou

A very interesting point in the link. In resume yes, it seems that trains really would physically fit in the tunnels and would enter and exit the tunnels without problems ... what they would not do is respecting the buffer space of security around that is required by current laws. As result if a train stops in some tunnels for an emergency the people may not have enough space for exiting the train safely and quickly (by modern standards).