Yes, it is possible for US passport Holders and Passport Holders of Schengen countries to get a three year tourist visa for Russia if you request regular processing only for your tourist visa application. You cannot request rush processing and get a three year tourist visa for Russia.
It will take the Embassy of Russia in Washington DC about 15 business days to approve this long term tourist visa for Russia irrespective of visa duration requested on your Tourist voucher and Confirmation from your hotel in Russia. Even if you request for 3 year tourist visa for Russia, the actual duration of the visa granted will be at the discretion of Russian embassy.
Your passport must be valid for 42 months beyond period of intended departure date from Russia and should have 2 blank visa pages remaining, not counting the amendment pages. If the passport does not have more than 42 months of validity left, then your visa will be good until 6 months from the date your passport expires.
You can apply for Tourist Visa for Russia for 3 years by Clicking Here