In message , Paul Scott
writes

Has that just been added today? I'm sure I didn't see it originally -
but (blown up) it doesn't look much like a normal railway coupling does
it - more like what you see on the back of a truck...

The photo's too small to be sure, but it looks like one of TfL's three
Plasser machines, that are equipped with buckeye couplers - not the
standard Wedgelock couplers used on passenger stock, and nor does it
have conventional drawhooks for emergency use, like most of the
engineering stock.

--
Paul Terry