In Copenhagen you move also with trains, the S-Trains. S-Trains are a surface metro service, travel only inside Copenhagen metro area and allow you to quickly go in any direction.

They're very frequent and always on time( on the station live timings there are arrival indications with an accuracy of 30 seconds).

They're very clean and comfortable and carry a handy display that visually tells you where you are on the track and which is the station you are approaching so you understand when you are going to get off the train.