In Sweden many trains run at 200 km/h (125 mph). Train types which currently attain this speed include the X 2000 tilting trains for long distances, the Regina widebody trains, the X40 double-decker regional trains, the Arlanda Airport Express X3, the MTRX-trains and the Stadler KISS-inspired double-decker regional trains. Since both the X2 and X3 are allowed to run at 205 km/h (127 mph) in case of delay,^{[citation needed]} they can technically be considered as high-speed trains. The X2 runs between many cities in Sweden including Stockholm, Gothenburg, and Malmö. The Arlanda Express trains connect Stockholm and Stockholm-Arlanda Airport.

Hundreds of kilometers of track are ready for 250 km/h (155 mph) 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 303 km/h (188 mph),^[1] with regular service at 250 km/h (155 mph) planned.

There are plans for a 180 km (112 mi) section of the Stockholm-Malmö line to be upgraded to allow for speeds of 250 km/h (155 mph). 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 250 km/h (155 mph) speeds (today 200 km/h (125 mph)) are long sections of Stockholm–Gothenburg, Gothenburg–Malmö, and Trollhättan–Gothenburg. A new Kramfors–Umeå line, Botniabanan^[2] has been ready for 250 km/h (155 mph) non-tilting trains since 2010, but train operators have not yet revealed plans for 250 km/h (155 mph) trains on Botniabanan, or on any other 250 km/h (155 mph) capable line. All these will be mixed passenger/freight railways.

The Swedish signalling system ATC does not currently allow for speeds higher than 200 km/h (125 mph), 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 250 km/h (155 mph). The ATC system in theory allows 250 km/h (155 mph) 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 250 km/h (155 mph) along 16 km (9.9 mi) east of Södertälje but no trains are approved for that.

SJ have bought trains (type X55, delivered 2010) that are prepared for 250 km/h (155 mph)^{[citation needed]} but limited to 200 km/h (125 mph) 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.

In December 2021, SJ announced that they are ordering 25 trainsets (Zefiro Express) which are capable of going 250 km/h (155 mph). 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.^[3] 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 Swedish government under Prime Minister Kristersson has issued a new directive for the Swedish transportation agency Trafikverket to end those plans.

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 200 km/h (125 mph) 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 300–320 km/h (190–200 mph) with non-tilting trains, dedicated for high-speed passenger trains.^[4]

In 2018 Chinese corporations became interested in building of Stockholm-Oslo high-speed line.^[5] 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.^[6]

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.^[7][8] 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 over 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.

The Borås–Linköping line will be built some years later than the first parts of Götalandsbanan. It has less potential for regional rail (still around 400,000 people live near this part of Götalandsbanan), but is of course needed for long-distance trains. Between Södertälje and Stockholm the existing railway with 250 km/h (155 mph) potential will be used. A southern extension to these lines, through Jönköping–Helsingborg–Copenhagen is considered economically unfeasible for the time being. Danish politicians are not very enthusiastic either.^{[citation needed]} Cost estimates are roughly 30 billion SEK for Borås–Linköping and 30 billion SEK for Jönköping–Helsingborg. The cost of the Helsingborg–Copenhagen line with a tunnel is hard to estimate, but 30 billion SEK is possible here too.^{[citation needed]}

The existing line through Linköping–Malmö–Copenhagen is however planned to be upgraded to 250 km/h (155 mph).^{[citation needed]}

These are realistic travel times based on the former plans to create a high speed railway network from Stockholm to Gothenburg and Malmö via Jönköping.

• High-speed rail in Europe