My dad shared a link with me about a neat new idea of how high speed trains could be boarded without ever fully stopping. Instead of stopping, the trains would slow down and be “docked” by another train carrying the new passengers.
New passengers on – departing passengers off – docking train disengages and returns for next group – high speed train ramps back up to full speed.
A different video shows how this could be accomplished using a slightly different technique where a docking pod stays on top of the high speed train between stops. This technique would require the high speed train to slow down a lot further, however.