while the traffic to the east was limited mostly to long-distance services, upgrading of the line began in berlin. first, the tracks of the berlin ringbahn (the circular railway, the eastern section of which opened in 1871), the lower silesian-märkische railway ("niederschlesisch-märkische eisenbahn-gesellschaft") from frankfurt (oder) and the eastern railway connected at a level junction near stralau rummelsburg station. from 1 may 1888, trains could run through the silesian station over the berlin stadtbahn to the centre of berlin and the lines to its west. shortly afterwards another pair of tracks was added to the northern half of the ringbahn to allow suburban trains to run independently of long-distance traffic.