[10] The construction of the 25-kilometre (16 mi) light rail line, without rolling stock or a depot, was projected to cost 274 million euros as of June 2016, with rolling stock and a depot projected to additionally cost up to 95 and 65 million euros, respectively.

The general plans to convert the congested bus line to light rail were first published in 2009, but the decision to begin construction was only taken in June 2016 after many delays.

[12][13][14][15] The municipality of Espoo has located the western terminus of the rail line at Keilaniemi instead of Tapiola.

The route is located entirely outside the current network, surrounding it; the length of the route constitutes a large proportion of the total network length, and the line is built to modern light rail standards (as opposed to the relatively old-fashioned street tram system).

However, the new line is technically compatible with the existing network (1,000 mm (3 ft 3+3⁄8 in) metre gauge, low platforms).

HSL (Helsinki Regional Transport Authority) organized an opening event at Otaniemi, with guests like Finnish prime minister Petteri Orpo, Finnish minister of Environment and climate change Kai Mykkänen and the deputy mayor of Helsinki.