In message
-sept
ember.org, at 08:54:30 on Sat, 8 Apr 2017, Recliner
remarked:

" . . . with many empty trains
running in the middle of the night . . .

Are these empty stock movements or trains for the
public to travel in?

I'm guessing that it means that GTR runs more passenger services than
needed at night, and fewer than needed during the day.

"more in the night" being a handful, "fewer in the day" limited by stock
availability [take a bow, DT] and track capacity - especially the
Thameslink core - [take a bow, Network Rail].
--
Roland Perry