Hah!! I went down to Westernport today and attacked The Wall over and over.
I made it 6 out of 9 times. The other 3 times, I fell. The first attempt, while I was fresh, I made it consecutively up all 4 blocks (each block a hill.... it's one 4-block-long hill, average grade 25%, interrupted only by the cross-streets.) You have to do all 4 w/o unclipping on race day to get a brick laid in the road.
After that, I just did the last section (31% grade), or the last 2, over and over, memorizing how to navigate the obstacle course of potholes and cracks (mostly 4-6 inches wide, several feet long, and at least an inch deep). I also developed a Plan B route up, in case there's someone in front of me on race day. I've determined that it's not so much an issue of strength as of balance and controlling the bike. There's a certain point before which I must not veer left; after that point, a slight left shift is helpful (Plan A) but not essential (Plan B.) I'll tell you what, I popped a few wheelies and wondered how I was still upright even though the bike seemed to have stopped moving forward, but 6 out of 9 isn't bad. At the top of one of the successful ones, I wondered, "Is my rear brake rubbing my wheel? Did itget knocked off center in that last fall? Feels like it was harder this time..." and then discovered I hadn't even been in my freakin' lowest granny gear!!!! Shoot, now I'll have to practice doing it like that >:-<
The tenth one.... well.... I started one last trip from the bottom of the 4 blocks and rode 3 of them, but then said, "Nahhhhhh......" and turned left instead of going up. I couldn't face it again and could tell I probably wouldn't make it. I was very, very tired.
There was a neighborhood boy about 12 on a mountain bike who tried it but didn't make it. He said sometimes he does, sometimes he doesn't. That particular time, I made it, and he gave me a thumbs-up and said "That's a hell of a climb." He also rode down it, which I absolutely will not try.
One injury per fall: right elbow bleeding in 2 separate places (from 2 of the falls) and right hip with a swelling, obvious broken capillaries, and a great big bruise on its way (I fell to the right each time).
I plan to go do this once a week until I know that street like the back of my hand and riding it is no big deal.