Freezing my Behind off at West Brompton waiting for a City District line service I heard a loud rumble from behind me. Then, heading towards Clapham junction (that's platform 2), came two class 73s coupled together. One was running electric (lots of sparking around west Brompton) and the other was running diesel. They were in a grey livery and the rearmost one had an unusual set of couplers.
Were these the Eurostar thunderbirds?