Christopher Christophi and Lucas Mazarrasa came up with this surprising concept for the eVolo skyscraper competition: The Hyper-Speed Vertical Train Hub. I don't really know how it would work—I'm guessing superconductors and magic—but I'd love to see it built, with all those maglev trains coming up and down the tower and in and out the tunnels under the megalopolis.
Here's their description:
The Hyper-Speed Vertical Train Hub aims to replace existing flagship train stations and create new key connective points for the exchange of people and goods with the new hyper speed network. The proposal will 'flip' the traditional form and function of the current train station design vertically, and re-form it into a cylindrical mass to increase the towers train capacity. This tall cylindrical form aims to eliminate the current impact that traditional stations have currently on land use, therefore returning the remaining site mass back to the densely packed urban Mega City. This remaining land will surround the base of the tower forming a large urban park, leading towards to the base of the Hyper-Speed Vertical Hub. Passengers will travel into the main lobby allowing travelers to ascend through the atrium and through the platforms and onto the carriages. The trains will create a dynamic and kinetic facade, one that will be continuously evolving and responsive to the workings of the vertical hub, a language that can be read by the whole city. As the train travels and transitions from its horizontal formation, and ascends up the facade vertically, the carriages will pivot similar to that on a 'Ferris wheel', allowing the passengers within the carriage to remain in an upright position and facing towards the cityscape. The carriages will be supported by a magnetic structure located at either side, eliminating the need for rails beneath, and allowing the carriages and its passengers to connect to the tower.