== Train length == 

 Regarding , well, I can state that HSTs have run as 9+2, but don't know of a source. As originally built, those for the Western Region and for North East-South West services were 7+2, and those for the East Coast Main Line were 8+2. Various reformations have occurred; most are now 8+2, with a few 7+2, but 9+2 do occasionally operate. ~~~~