Actaully the 319s are all Mk3 derived, remember that 317s are also cleared through the Thameslink tunnels to Moorgate. The tightest parts of the tunnels are near Kings Cross..
http://www.semgonline.com/gallery/class319_01.html
Class 321s are 317s without gangways..
The 325 is essentially a freight version of the 317 but with networker cabs.
All have more in common with the Mark 3 then the Class 156 ever did. That was Metro Cammell's own design, they just used a lot of common parts (windows, cab layout) for commonality. --Enotayokel (talk) 10:08, 19 April 2008 (UTC)[reply]__DTELLIPSISBUTTON__{"threadItem":{"timestamp":"2008-04-19T10:08:00.000Z","author":"Enotayokel","type":"comment","level":1,"id":"c-Enotayokel-2008-04-19T10:08:00.000Z-corrections","replies":["c-Sunil060902-2008-05-19T16:13:00.000Z-Enotayokel-2008-04-19T10:08:00.000Z"]}}-->
- OK, I guess you're right! Sunil060902 (talk) 16:13, 19 May 2008 (UTC)[reply]__DTELLIPSISBUTTON__{"threadItem":{"timestamp":"2008-05-19T16:13:00.000Z","author":"Sunil060902","type":"comment","level":2,"id":"c-Sunil060902-2008-05-19T16:13:00.000Z-Enotayokel-2008-04-19T10:08:00.000Z","replies":[]}}-->
