The Transport for London website now has sets of 3 snapshot track diagram
pictures (for Press use) showing the locations of trains leading up to
both the Aldgate and Edgware Road explosions. In the latter case it is
clear that the bomb was on an Edgware Rd-Paddington Circle line train (no
214) between Edgware Rd and Praed St Junction. When the bomb went off it
was passing a (stationary) eastbound train from Paddington to Edgware Rd
(presumably a District since there is no train ID no shown). This was
evidently waiting for a free platform at Edgware Rd. There was an
eastbound H&C at Edgware Rd, plus another train which had been stationary
at the south side of the eastbound island platform for some time (probably
a reversing District Line train). Only Circle line trains have IDs
showing, the others are all "000" but can be identified from following
through the picture sequence.

http://www.tfl.gov.uk/tfl/press-cent...ry/default.asp
and accept the copyright T&Cs to find the pictures.

David