A spokesman for the North East Economic Development Initiative (NEEDI), which is drawing up a feasibility of study of running trains through the tunnel, said: "This could be game-changing for the region.
The NEEDI spokesman said: "The Metro is used by tens of millions of people every year but the opportunity to add a new line is a once-in-a-generation possibility.
The UN last month warned El NiAaAaAeA~o could drive the number of people needi aid soaring by over 80 percent, from some 12 million people at the start of 2015 to over 22 million people by the start of 2016.