In North Norfolk we have a preserved steam railway line. It runs from Sheringham to Holt. The Christmas train is covered in coloured lights. The line is not electrified. How are the lights powered? I have not had time to find out. Any ideas?
https://www.bbc.co.uk/news/av/uk-england-norfolk-50504911/norfolk-lights-express-makes-poppy-line-debut
Z.