When it comes to reducing the rail systems' ecological footprint, it is essential to assess and compare lifecycle (LC) greenhouse gas (GHG) emissions. In the presented study this is executed for the two main railway track construction types: ballasted track and slab track. Preexisting soil conditions are considered as they significantly influence maintenance demands, service life and consequently life cycle costs. This study is executed for Austrian boundary conditions with speeds up to 250 km/h. The degree of emission reduction varies according to the additional soil reinforcement treatments employed, which in turn depend on the preexisting soil conditions. The findings indicate that the use of ballasted track leads to 11-20% lower LC GHG emissions. Poor soil conditions can increase LC GHG emissions for both track designs by as much as 26%, underscoring the importance of incorporating this parameter into the railway track lifecycle assessment (LCA). Compared to slab track construction, this type results in increased concrete mass and necessitates more extensive soil enhancement measures due to the track panel's greater rigidity, despite its longer service life. In tunnel areas, GHG emissions are lower using slab track as soil reinforcements are not required owing to the pre-existing concrete base. Material production accounts for more than 80% of GHG emissions in both construction styles. Therefore, the circular economy and advancements in steel and concrete production processes have vast potential for decreasing GHG emissions.