Reivindicaciones

1. Metropolitan transport method, characterized in that it comprises running at least one first train (1) in a first direction, defined from a starting point to a finishing point of a route comprising a plurality of stopping stations (2, 2'), where said at least one first train (1) runs through a tunnel (3) comprising at least two levels (4, 5), said at least one first train (1) running on a first level (4) of the tunnel (3) and stopping at all the stopping stations (2, 2') on the route; the method also comprising running at least one second train (6) in the first direction of the route on the second level (5) of the tunnel (3), where said at least one second train (6) does not stop at all the stopping stations (2, 2') on the route. 2. Metropolitan transport method according to claim 1, characterized in that it comprises running at least one third train (7) in a second direction defined from the finishing point to the starting point of the route running on the first level (4) of the tunnel (3) and stopping at all the stopping stations (2, 2') on the route; the method also comprising running at least one fourth train (8) in the second direction of the route running on the second level (5) of the tunnel (3), where said at least one fourth train (8) does not stop at all the stopping stations (2, 2') on the route. 3. Metropolitan transport method according to any of the preceding claims, characterized in that said at least one train (6, 8) running on the second level (5) stops every four stopping stations (2). 4. Metropolitan transport system working according to the method defined in any of the preceding claims, characterized in that it comprises a plurality of first stopping stations (2) operatively configured so that the trains (1, 6, 7, 8) running on said first level (4) and second level (5) stop; comprising a plurality of second stopping stations (2') operatively configured so that only the trains (1, 7) running on the first level (4) stop. 5. Metropolitan transport system according to claim 4, characterized in that the second stopping stations (2') can be converted into first stopping stations (2) by incorporating installations. 6. Metropolitan transport system according to any of claims 4 and 5, characterized in that the first level (4) of the tunnel (3) is above the second level (5).