Top ground speed transportation has roughly doubled since the 60's. If Elon Musks hyperloop gets built, then you could see that become 3-4 times faster.

http://en.wikipedia.org/wiki/Land_speed_record_for_rail_vehi...

And there is of course the scramjet http://en.wikipedia.org/wiki/Scramjet which set records in 2003 which is 10,000kph faster than the record set in 61.