Can anyone help

While waiting for a District line yeasterday (Saturday) at about
15.30ish at West Brompton. What came along on the NR Silverlink
platform (in service) to Willesden Junction was a 2-car diesel set from
the Barking-Gospel Oak line (Sorry... I'm not into train codes) instead
of the usual 3-car electric set. Is this unusual as I have never seen
this before. Does anyone kinow why this happened?

I do know that they had engineering works taking place on the B - GO
line yesterday


Regards


Jeff