The Network Rail JSON used for this project is both rich and relatively complex. Some of the fields are embedded arrays and the census field is an array with two columns, showing the counts for multiple types of users.
Work is in progress on bringing it all into the SQL database and the Looker Studio report, and this section will be updated accordingly.
Let's let the SQL speak for itself.
This is just the main table – any field that represents an array has its own dedicated lookup and junction tables.