The project involves constructing a 7.2km double-track underground line branching off the existing line to Helsinki Central south of Pasila, with three new stations serving Töölö, City Centre and Hakaniemi. This will allow some commuter services to be diverted away from the Pasila – Helsinki Central section, easing congestion on the existing line, which will come under increased pressure with the completion of the Ring Line project next year. It will also significantly improve rail access to the districts of Töölö and Hakaniemi.

The Finnish Transport Agency and the City of Helsinki have already completed a general plan and an environmental impact assessment, and an initial public consultation has also been carried out.

The TEN-T grant will fund geological investigations, mapping and field surveying, and identification of station locations and route alignment options.

Following the completion of the planning phase, the Finnish parliament and Helsinki City Council will decide whether to proceed with the €740m project, although this is not expected until late 2014 at the earliest. The Finnish Transport Agency says it expects the City Loop to open in 2020.