Moving Platforms from Priestmangoode is a conceptual system that would allow high-speed trains to transfer passengers while in motion. Created by Paul Priestman of Priestmangoode, the system is designed to make high-speed rail travel more efficient by eliminating the need for stops.
The Moving Platforms system works by having the slower local trains and trams pull up alongside of a high-speed train. The high-speed train slows down and docks with the regular train, acting as a moving transfer. A design such as Moving Platforms could really go a long way with regards to getting the public to accept a high-speed rail system. You can see a conceptual design of Priestman's Moving Platforms here. American airline companies, consider this your warning.