Here in the UK we use the “third rail” system to power our trains. Snow and ice on the line makes it difficult for trains to draw power from the third rail. When this happens, trains can become stuck or "fail".
In very cold weather, we try to stop ice forming on the rails by running de-icer trains and empty or ‘ghost’ trains through the night.
We know you need to get to work, but sometimes it’s just not safe to run our trains. We take guidance on this from Network Rail, which manages the UK's railway infrastructure.