There have been four cyber-attacks against the UK railway network this year, and security experts are genuinely worried about it.
They say that a hacker with enough knowledge about the network can do some serious harm. People could be killed. One of the key reasons why this hasn't happened already is, researchers believe, because the order hasn't yet been given.
Yes, they believe the attacks are state-sponsored. They're not sure which state is targeting the country's railway network, though.
The attacks were spotted by Darktrace, a private security company guarding the UK rail network, and a Kaspersky Lab researcher said he found 'several' weaknesses.
He told Sky News: "Hackers can get access not only to simple things like online information boards or in-train entertainment, but also to computer systems which manage trains by itself, which manage signals, manage points, and in this case, if they have enough knowledge, then they can create real disaster related to train safety."
"So they have access, they monitor, they collect intelligence but they don't try to create a disaster. Why? I believe that they don't have the order at the moment. But in case of any maybe warfare, it can be an option to use cyber weapon against civil infrastructure. And this is scary."
However, the Department of Transport says they're doing all they can to keep the network safe.
"We keep rail security under constant review and we are working with industry to ensure that all risks to the rail network and other infrastructure are minimised,” a spokesperson said.