There is a passage in there that isn't very clear---I think it has confused you LaForge. It says that Merckx had road frames built that replicated his track frame, and trained on the road using those frames. But the way it's written, it makes it sound like his track frame was a road frame, which it certainly wasn't.
Here's a picture of the bike Merckx is supposed to have ridden on that day, now on display at Merckx metro station in Brussels. Apparently there's some doubt as to whether it's actually the same bike. Someone who knows more than me should pipe in. At any rate I do know that the bike Merckx rode was ultra light, with lots of exotic metal and drillium. Still googleing for the article...
Edit: this is it! Sorry about the annoying separate pages but it's really good nonetheless. It looks to be the same article LaForge linked to, but with pics and a bit of bike nerdy info on the bike---measurements, component list, etc.
http://www.classicrendezvous.com/Ben..._B-guide_1.htm
