they used to, for certain construction projects (harbor, hydro dam). but none currently, although a passenger light rail has been proposed around their capital
Low population, heavily concentrated in one city, with little heavy industrial activity, coupled with very unforgiving terrain (steep volcanic grades) and even more unforgiving weather (severe frost heaves/thermal fluctuation, huge snow load).
there’s just no economic reason to build difficult railways when your entire country is like 300mi across and never moves enough stuff in bulk to need it. including people.