At a rail yard near Milton Keynes, a group of men in orange outfits are making final checks on huge slabs of railway track, preparing them so that they are ready to be installed over Christmas and New Year.
At a time when many commuters stop work to enjoy celebrations with friends and family, rail bosses get massive engineering projects and upgrades done.
So, those orange-clad workers are out in force.
Carl Foy has been on duty for roughly 20 of the 27 Christmases in his career. This year will add another to the tally - with his two grown-up sons, who are also rail workers, out there with him. Some friends think he's mad for doing it. But Carl says it's just accepted as part of the job.
"We bring in a few mince pies, the site offices might have a bit of tinsel around," he says. "We make it as enjoyable as we can and just crack on with the work."
