The running tunnels are constructed by so called shield tunnelling, assembled of reinforced concrete segments. The trains will run in both directions in separate one-track tunnels. An alternative solution can be considered on the section under Thkly t, specifically, using a method of shallow construction from the surface. Further detailed investigations are necessary to make a decision on this issue.

Wayside engineering structures are constructed by mining method, so called shotcrete technology and double lining. First of all, a shotcrete external lining is prepared, then a water-proof internal lining is made of in-situ concrete.

• To enable train reversal, a track connection is made in Rkczi tr station on the side of Klvin tr station to enable possible section by section operation, or fast discarding of broken down trains.
• An individual ventilation structure will be constructed in the longest section between two stations, Ttnyi t and Bocskai t stations.
• Main water pump stations will be constructed at the lowest points of running tunnels.
• Both running tunnels will be connected by cross tunnels of appropriate spacing. Purpose of the connection is to provide escape possibility from one tunnel to another.

Structural development of the stations will be determined by the vertical alignment of the section concerned. The depth of stations from surface varies between 12.90 and 30.30 m, the deepest one is Szent Gellrt tr station. This relatively shallow line alignment enables the construction of almost all stations from the surface, in open working pit, as box structures. Work pits are supported by diaphragm or sheet pile wall. The inside of the box is divided into various levels by horizontal or curved reinforced concrete slabs. Platforms, escalators, elevators and service rooms are located within the box. At some of the stations - due to the high building density on the surface - only some part of the station can be constructed as a box, the other part requires mining method or shotcrete technology.

• A depot will be constructed in an area of about 84,000 sq. m. near the MÁV railway station in Kelenföld, which is intended for vehicle storing, periodic maintenance and repair of tunnels, railway tracks, various buildings, electric and mechanical installations etc.
• Kelenföld pu. station is located between Őrmező and Etele tér under the tracks of this railway station, perpendicular to the tracks. The station is connected to the engineering structures of the reversing track and the head-shunt towards the depot. Both exits of the station provide for connection with the MÁV (railway) station and long distance bus terminals, terminals of BKV (Budapest Public Transport) lines and other surface facilities.
• Tétényi út station is planned to be located at the border of a district centre and the neighbouring park located at the corner of Tétényi út and Etele t. It has its exit connected to a surface hall through escalators and elevators.
• Bocskai út station will be constructed under Fehérvári út, southwards from Bocskai út junction. Its exit will lead to a subway already under construction in this junction.
• Móricz Zsigmond körtér station is constructed in the junction of Bartók Béla út and Fehérvári út, under the eastern side of the square. Its exit is connected to an already constructed subway.
• Szent Gellért tér station is located under Műegyetem rakpart and building CH of the Technical University. Its escalators will lead into an underpass to be constructed opposite the end of Budafoki út.
• Fővám tér station will be located in front of the University of Economy, under the track of Tram Line 2 (upper embankment), under the lower embankment and partly under the Danube. Its exit leads to the level of underpasses under the stop of Tram Line 2.
• Kálvin tér station will be constructed in Kálvin tér, on the side towards Ráday utca and Lónyai utca, in the place of the existing underpass corridor. The top floor of the station will be a new underpass level, which will substitute the demolished underpass. The station will enable changing to Metro Line 3 by an escalator connecting to the station from below.
• Rákóczi tér station will be located under the park of this square. Its exit will face Nagykörút enabling a direct change to Tram Lines 4 and 6.
• Népszínház utca station will be constructed at the corner of Köztársaság tér toward Népszínház utca. Its exit will lead to the underpass level.
• Keleti pu. station will be located at the northern side of the square, in the extension of Thököly út, between Rottenbiller utca and Bethlen Gábor utca. Both exists will lead into the underpass.
• Dózsa György t station will be constructed under Thököly t, east of Dózsa György út. Its exit will be connected by underpass to Népstadion and the surrounding sports facilities.
• Hungária körút station will be under Thököly út, between Hungária körút and the railway overpass and the railway station, with direct underpass connection to Tram Line 1 and the MV (railway) station in Zugló.
• Róna utca station will be located under Thököly út, west of Róna utca. Its exit will lead to the underpass at the road junction.
• Bosnyák tér station will be constructed under Thököly út as well, east of Nagy Lajos király út. Its exit will be connected to the underpass at the road junction.

Surface rearrangement will occur around each Metro station, and the reconstruction works started with the rehabilitation of Bartók Béla t will be resumed in the areas, roads, squares along the new Metro line (e.g. Baross tér, Thököly út).

Considerable public utility construction works will be required on the construction sites. The large-scale surface rearrangement works will also require further utility replacement works, including the connections of water supply, sewage and power supply systems.