Just thought you alls would find this interesting -- a cyclist I know just had both seat rails of his B17 break during a ride. He posted this to our club listserve:

"I got it back in 2000, used it for a couple of years on my
tandem, then put it on the Kogswell when I started commuting on it in
2006. It had around 17,000 - 18,000 miles on it.

It's not the first time I've had a seat rail break, but it is the first
time I've had two fail at once."

This man has a bunch of bikes, and I'm pretty sure they all have Brooks saddles. He rides a lot. I mean really a lot.