Hello Don, They call it twin lateral tubes or twin lats. The Galibier is an improved on copy of a French Jaques Schultz. The Shultz is minus the twin top tubes, great improvement by Harry Rensch in fitting these top tubes. Later Tom Board used thicker seat stays as opposed to the earlier versions which were constructed with pencil stays. He also used a steel called T45 (this has a breaking strain of 45 tonnes). This is used for the drop tube (vertical tube housing the bottom bracket). Now these are wonderful Galibier's not that there was much wrong with the original ones. Don't believe the rubbish on the Hetchin's site I quote "The odd frame geometry was not a success: the bottom bracket has too little support due to the missing down tube and is not stiff enuf to race". They had more road race success to their name than Hetchin's just read the record books a name to look for is Clive Parker.
Thats all for now. Keep those wheels spinning, in your memories if not still on the road. Be lucky Mick Butler Huntingdon UK.