On the morning that many Britons returned to the office after months of working from home, the pingdemic saw commuters squeezed onto reduced services due to rail staff self-isolating.
Train operators have been forced to slash the number of trains on the tracks on Monday morning because drivers and guards are stuck at home.
But commuters have been left with just one train an hour on busy lines into London, with reports of passengers sitting in the aisles while government advice is to maintain social distance.
The transport union RMT has called for all rail workers to be added to the pingdemic exemption list that would allow staff to return to their place of work if they tested negative on a given morning after being alerted to self-isolated due to being a close contact.
The union’s general secretary Mick Lynch, asked if he was any clearer on Monday as to how the situation affected his members, said: "No, it’s completely unclear we’ve been trying to find out over the weekend exactly what’s happening. At the end of last week we had this very restricted exemption programme put to us, where individuals had to be named.
"Then over the weekend we had this breaking news that it was going to be a more generalised exemption process.
"I’ve tried to contact the employers to find out what they know, they know as much as I do, which is very little. And as far as they’re concerned, the only update they’ve had from the both the transport and the authorities is that it’s the limited exemption that we heard about for limited number of signallers and people in control rooms last week.
"So it’s under confusion and chaos, nobody knows what’s going on, and the authorities, simply not telling the employers, the trade unions, the workers, or the authorities what they should be doing."
He added that the Government’s guidance gave "very little" about "protecting the people that are having to work" with someone who might have been pinged.
"So if you’re working on board a train or working in a control room, and you are supposed to be isolating, you are enhancing the risk to the other people working around you, whether they’re passengers or colleagues on the railway," he told the Today programme.
"There’s very little said about protecting the people that are not isolating their working normally with people who really aren’t aware of the effects of the thing."
Commuters’ frustration as workers return to office