HÉV used to reach the city centre, but was cut back when the metro was built, necessitating a change of trains at Örs vezér tere with passengers having to use an underpass. The new link will make it possible to connect the two lines and introduce dual-voltage trains which can use both the third rail and overhead power supply systems.

 

A detailed feasibility study concluded that the project will make commuting easier for 40,000 people and that travel times will be reduced by 30% while headways will be cut on the HÉV line as extended metro services will supplement existing HÉV services.

Budapest also voted to allocate Forints 1bn ($US 3.6m) in 2016 and 2017 towards completing authorisation plans for the whole project and building plans for the first phase. The scheme will be split into several phases in order to secure continuous funding.

The total cost of the project is estimated at Forints 200bn which includes rebuilding the single-track Csömör branch and purchasing new trains. Alstom supplied new trains for Line 2 only three years ago and it is proposed to either transfer them to Line 3 or sell them.

The project involves constructing a new underground station at Örs vezér tere, a new station on Line 2 between Puskás Ferenc Stadion and Pillandó utca, two new stations on the HÉV section, putting two existing stations underground, diverting the eastern end of the HÉV line onto a new alignment, and building a new depot. Construction is expected to be completed in 2020-2022.