There are also three other major projects on the table. The first would elevate a large segment of the San Martín Line which runs through the city center and electrify the line, while the second would see the electrification and extension of the Belgrano Sur Line to Constitucion station in the city center. If these two projects are completed, then the Belgrano Norte Line would be the only diesel line to run through the city. The third and most ambitious is to build a series of tunnels between three of the city's railway terminals with a large underground central station underneath the Obelisk, connecting all the commuter railway lines in a network dubbed the Red de Expresos Regionales.