When I was involved with Track Renewals as a Site Engineer, it was quite common for me to turn up at the office in a morning and nearly complete a full day in the office before the phone rang and the booked night shift Tech dropped out.
Could I cover the job?
So 07.30 - 15.00 then a couple of hours kip, 2 - 3 if lucky then out on site 21.00 - 07.00
When booked on nights myself, I could never get a full 8 hours before or after a shift but used to do 2 - 3 hours if possible before and maybe 4 when I got home. I often heard every presenter on R2 over a 24 hour period.
The worst shifts were on blockades when instead of 8 hour shifts on site, 06.00 - 14.00 - 22.00 - 06.00 someone decreed we would do 9 hours on site which meant every day we rolled 3 hours forward 06.00 - 15.00 - 00.01 - 09.00.
By the end of 9 days you did not know what day it was.
Never doing that again.
Take my hat off to the "orange army" doing infrastructure work. Doing a night shift is one thing, doing a night shift which involves hard labour is something else.