Above is a link to an electric train experiment you can carry out using wire and batteries. With an adult, carry out the experiment and have a go at writing up your experiment too. Top Tip: you can find some free KS1 experiment writing templates online.
The London Underground and overground trains run on electricity. Follow this link to learn more about electricity and circuits: https://www.bbc.com/bitesize/topics/zj44jxs
Now draw your own diagram of a circuit using the appropriate electrical symbols. Perhaps you could make your own real life circuit with the help of an adult