In Europe, the EU requires its members to separate the national
railway infrastructure managers from
railway undertakings which are public and private companies providing services by operating
rolling stock. This ensures conditions enabling the latter companies to
compete fairly among each other, with multiple companies
bidding for the privilege to operate the line for a limited time period under
public service obligation aided by
railway subsidies or under
franchising. In addition, other companies offer trackside and rolling stock maintenance. Some countries have in turn a national railway company that owns all track and operates all trains in the country, for instance the
Russian Railways (the world's largest rail company by network size). Other countries have many different, sometimes competing, railway companies that operate each their own lines, particularly in the
United States and
Canada. Countries may have both public and private railway companies, for instance the United States, where the publicly-owned
Amtrak exists alongside numerous private operators. ==See also==