Running slower than it is supposed to or broken down frequently. So, the trains still come every 3-5 minutes, but it takes (for example) twice as long to get th

Running slower than it is supposed to or broken down frequently. So, the trains still come every 3-5 minutes, but it takes (for example) twice as long to get there sometimes (track problems causing them to run trains slower than normal, or just being stopped for an arbitrary amount of time). So you end up 20 minutes late to your job. So if you absolutely have to be there on time, you have to leave 20 minutes early (at least). And in my experience there is no cell service when you’re in the tunnels, so you can’t even let your work know there’s a problem.