The Yellow Line is estimated to cost nearly 14 billion Swedish kronor, with the majority of the funding coming from the state.

[4] The initiative for a new line to the west of the city centre, avoiding Slussen, began with the Stockholm Negotiations (Swedish: Stockholmsförhandlingen) in 2013, which involved talks between the government, regions, and municipalities on improved public transport and urban development.

[5] In spring 2017, an agreement was reached to build a new line connecting Fridhemsplan and Älvsjö, including a stop at Liljeholmen.

[6] Planning for the line began in 2020, including a study to assess potential routes and station locations.

[9] In 2025, plans will be submitted for the line's official approval, and construction is expected to start later that year, pending all necessary permits.

[1] The Yellow Line will be approximately 8 km long, running north to south, to the west of the city centre.

[11] This is due to differences in the line's technologies and a design, including shorter platforms and autonomous train operation.

A connection between the depot and nearby Western Main Line, to facilitate the movement of trains and maintenance vehicles, is being investigated.

The trains will not have driver cabs, allowing for additional seating and views of the tunnel, similar to the system used in the Copenhagen Metro.