Maybe a little discussion of the "Campagnolo Model" Brooks is in order.
A normal frame only allows the saddle to be pushed back to a point where the post is in line with the center of the saddle. Narrow rails allow the saddle to be pushed way back past center. Sounds like a clear improvement and a great idea, right?
Well the thing that killed it is that the saddle tends to move from side to side in the saddle clamp because the "base" is too narrow.
Just another example of a part that disappeared because it had fatal flaws (re: bivalents) and has since become a hot collectable in spite of its original design shortcomings.
Chuck Schmidt
SoPas, SoCal
http://www.velo-retro.com (Reprints, T-shirts and Campagnolo Timeline)