On 2009-12-16 23:17:06 +0000, MIG said:

On 16 Dec, 22:47, John B wrote:
On Dec 15, 8:36*pm, (Neil Williams)
wrote:

On Tue, 15 Dec 2009 05:34:52 -0800 (PST), MIG

wrote:
Not quite 20 years. *The 321s must have been introduced later than
that, and still flush on to the tracks.

Really quite surprised by that, given that they're just a later build
of 319s with a different front end.

I was kind of surprised a few years ago when I first noticed it.

Mind you, they were plugged as something very new and special before
they were introduced, and turned out to be 317s with a sexier front.

Didn't the 317s originally have retention tanks for Moorgate use?