Upgrades to existing lines Hundreds of kilometers of track are ready for operation, with the exception of signaling systems,
catenary, and the trains themselves. A modified
Regina test train, called "the Green Train", has attained a maximum speed of , with regular service at planned. There are plans for a section of the Stockholm-Malmö line to be upgraded to allow for speeds of . The implementation of these plans has been postponed indefinitely as a decision is pending on the construction of a new parallel high-speed railway. Other railways that will eventually allow speeds (today ) are long sections of
Stockholm–Gothenburg,
Gothenburg–Malmö, and
Trollhättan–Gothenburg. A new
Kramfors–
Umeå line,
Botniabanan has been ready for non-tilting trains since 2010, but train operators have not yet revealed plans for trains on Botniabanan, or on any other capable line. All these will be mixed passenger/freight railways. The Swedish signalling system
ATC does not currently allow for speeds higher than , and current plans only allow for higher speeds with the
EU-wide
ERTMS signaling system. Botniabanan has had this system in operation since 2010, allowing . The ATC system in theory allows but that would require reinstalling track equipment such as signal boxes, overhead catenary systems and signals as ATC uses point based transmission, and higher speed means new points of transmission. ATC is installed for along east of
Södertälje but no trains are approved for that. SJ have bought trains (type
X55, delivered 2010) that are prepared for but limited to until a later date. In December 2021, Swedish national railway company
SJ ordered 25 Zefiro Express trainsets with an option for 15 more from Bombardier Alstom, that will be capable of 250 km/h (155 mph). The trains are planned to be in service from 2026.
New trainsets In December 2021, SJ announced that they are ordering twenty-five
SJ 250 trainsets (based on the
Zefiro Express platform) which would be capable of going . They are expected to go into service in 2026, and will complement the
X2000 service on the busiest lines (Stockholm—Gothenburg/Malmö) as well as cross-border traffic with Denmark and Norway. This should be seen as an investment to be able to utilise the faster speeds of the planned new mainlines from Stockholm to Gothenburg/Malmö via Jönköping, although the
centre-right Swedish government under Prime Minister
Ulf Kristersson has issued a new directive for the Swedish transportation agency
Trafikverket to end/review those plans, and later decided to continue with parts of the plan such as the
Ostlänken (The East Link) project,
Gothenburg–
Borås double tracks and
Hässleholm–
Lund quad tracks.
New lines There were plans for completely new high-speed railways
Stockholm–
Linköping–
Jönköping–
Borås–
Gothenburg ("
Götalandsbanan") and
Jönköping–
Helsingborg–
Copenhagen ("
Europabanan" for the Swedish part), since the existing railways are relatively congested, with mixed passenger trains, slower regional trains and even slower cargo trains. The plans said that the new railways would be built similar to the French
TGV-lines with long curve radii and relatively steep inclines allowing for speeds between with non-tilting trains, dedicated for high-speed passenger trains. In 2018 Chinese corporations became interested in building of Stockholm-Oslo high-speed line. Trafikverket awarded
American engineering firm
Jacobs Engineering Group with the contract to consult on a proposed $24 billion high-speed rail network linking Stockholm with Gothenburg and Malmö. In late 2022, the then
newly elected centre-right Swedish government decided to completely abandon Sweden's high-speed rail project due to rising costs. Its new directive to the
Swedish Transport Administration (Trafikverket) in late December stated that Trafikverket shall pause planning of all sections and analyse how costs could be lowered for the Borås – Gothenburg, Ostlänken (
East Link project; Stockholm – Linköping) and Europaspåret (Jönköping – Hässleholm). It motivated this by the rising costs and wanting to increase regional passenger services, therefore not wanting to complete the whole high speed railway network project. However, Trafikverket has stated several times that it is impossible to further increase services on most lines where its needed due to full capacity on both the
Southern Main Line and
Western Main Line. Critics has pointed out that this makes it harder to increase railway cargo traffic, going against Swedens and the EU's promises to lower emissions. Also, a partial upgrade of the mainlines from
double-track to
four-track railway on busy sections, instead of building new double-track lines, would lead to major disturbances during the period of construction, as well as creating single points of failure where a large part of railway traffic would be halted if for instance an accident occurs on the line. However, the government later chose to continue parts of the high-speed rail projects such as the
Ostlänken (The East Link) project,
Gothenburg–
Borås double tracks and
Hässleholm–
Lund quad tracks. == Major expansion projects ==