According to the announcement by Budapest Mayor István Tarlós passengers will be able to start using metro line M4 from 12:00 noon on Friday, 28 March 2014. The new metro line will be operating until the last scheduled departures on Friday while the surface transport network will remain unchanged: buses will be operating based on their current schedules and routes until the following day; the new public transport service changes will apply from the first scheduled departures on Saturday, 29 March 2014. Free travel is offered on metro M4 from 12:00 noon until the last departures on Sunday 30 March 2014. This special free service does not apply on the surface transport and the other metro lines. As ticket validating machines will be out of service on metro line M4 on the above days, when transferring to lines M2 or M3 at Keleti pályaudvar or Kálvin tér, respectively, tickets will be validated manually by personnel. On Monday, 31 March 2014 from the first departures regular fares apply on the new metro line as well.
The state-of-the-art metro will run between Keleti (Pest side) and Kelenföld (Buda side) railway stations on 7.4-kilometre-long tracks in 13 minutes crossing underneath the Danube. Similarly to the other metro lines, M4 will run every 2-3 minutes during peak hours, every 5 minutes during the day and at weekends, whereas late in the evening the headway will be 10 minutes.
Most of changes of the surface network affect Southern Buda, the city centre, Zugló and Újpalota as well as Budaörs and Törökbálint. For details of the new surface network, check out bkk.hu/m4.