The RAIB have just issued their report into the derailment (at slow speed and without injuries). I mention it here as there is a good deal of signalling interest in the report - see https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/574435/R242016_161206_Ealing_Broadway.pdf.
In summary a TC failure late at night and communications problems between signallers and the line controllers at different locations led to a point not being set correctly for the train to safely proceed.