Interrail

The Interrail Pass is a rail pass available to European residents. Residents of countries outside Europe may purchase the Eurail Pass instead. Types of Interrail Pass include the Interrail Global Pass, the Interrail One Country Pass, and the Interrail Premium Pass.
The pass allows unlimited rail travel in (and between) all 33 participating countries for a certain period of time. High-speed trains and night trains often require a paid seat reservation. The Interrail One Country Pass allows unlimited rail travel within one European country.
Eligibility.
Interrail passes are available to those who "are citizens or official residents from one of the countries of the European Union or one of the countries listed hereafter" (Eurail is for citizens or official residents of countries "not in the EU or not listed hereafter"): Albania, Andorra, Belarus, Bosnia-Herzegovina, North Macedonia, Gibraltar, Iceland, Kosovo, Liechtenstein, Moldova, Monaco, Montenegro, Norway, Russian Federation, San Marino, Serbia, Switzerland, Turkey, Ukraine, United Kingdom and Vatican City. Proof of citizenship may be a passport, identity card, or government-issued residency document.
Age categories.
Interrail Passes three age categories and the full fare (adult fare):
Types.
Interrail Global Pass.
Coverage.
The Interrail Global Pass is valid in the following European countries: Austria, Belgium, Bosnia-Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Great Britain, Hungary, Ireland (Republic of Ireland and Northern Ireland), Italy, Latvia, Lithuania, Luxembourg, Montenegro, the Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Switzerland, Sweden, and Turkey. Interrail Global Passes include ferry crossings from Patras and Igoumenitsa (Greece) to Venice, Ancona, and Bari (Italy) operated by Superfast Ferries and Blue Star Ferries; fuel surcharges, port taxes, high-season supplements, and cabin accommodations are extra.
Interrail passes are not valid on railways in Albania and the countries of Belarus, Moldova, Russia, and Ukraine. There are no railways in Andorra, Cyprus, the Faroe Islands, Gibraltar, Iceland, Malta, or San Marino. L'Hospitalet-près-l'Andorre in France is the closest railway station for Andorra. Rimini, in Italy, is the closest station for San Marino.
Country of residence.
Until the end of 2015, Interrail passes were not valid in the traveller's country of residence, although a discount was granted on journeys to or from the border. On 1 January 2016, the pass became valid for two free journeys in the traveller's country of residence: one to and one from the border. The limit exists to prevent people from using Interrail for work commuting and business travel.
Validity.
The Interrail Global Pass has the following validity options:
Interrail One Country Pass.
The One Country Pass allows unlimited travel on the rail network of one country, with unlimited journeys on each travel day. One-country passes are available for three, four, five, six, or eight travel days within one month for each of the following countries: Austria, Benelux, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Great Britain, Greece, Greek Islands, Hungary, Ireland (Republic of Ireland and Northern Ireland), Italy, Latvia, Lithuania, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland and Turkey.
There are no separate passes for Belgium, Luxembourg, and the Netherlands, but there is a Benelux pass. It is also available to residents of Belgium, Luxembourg, and the Netherlands, but it is only valid in the two countries other than the country of residence.
Reservations.
With an Interrail pass, reservations are usually not required for local and regional trains; however, reservations are needed for most high-speed, international, and night trains. Surcharges are required in many countries to guarantee seat reservations and other benefits, such as meals, drinks, free Wi-Fi, and access to first-class lounges. These reservations can usually be avoided by taking regional or local trains. Reservations may be made at the station, on the rail-company website, with the Rail Planner app, or at a travel agency.
High-speed trains.
Many high-speed trains require reservation and, sometimes, an extra fee sold as a supplement or pass-holder fare: 
Night trains.
In addition to high-speed trains, many overnight trains require reservations (at extra cost) for sleeping accommodations such as couchettes or sleeping cars; some trains have only sleeper cars. With Interrail's Flexi Global Pass, a direct overnight train leaving before midnight only uses one travel day (the day of departure).
Reductions on privately owned trains.
Although Interrail passes are normally valid only on national railway systems, some private rail systems offer free or discounted service (usually 25 to 50 percent) to Interrail pass holders.
DiscoverEU.
In 2015, German activists Vincent-Immanuel Herr and Martin Speer approached European Commission vice-president Frans Timmermans with a proposal to provide all EU youth with a free one-month Interrail Global Pass
at age 18. Their effort was documented by Politico Europe's "Brussels Playbook". According to Herr and Speer, their idea would help to overcome stereotypes in Europe and problems with nationalism in several countries by enabling a whole generation (not just a small fraction of it) to explore Europe. They subsequently wrote a number of articles about their idea, started a change.org petition, and approached more EU politicians. 
The idea was picked up by a number of EU politicians in 2016, including Rebecca Harms, Karima Delli, Michael Cramer, István Ujhelyi, Manfred Weber, and Alexander Graf Lambsdorff. A 2016 German survey found that 56 percent of respondents were in favor of such a proposal, and Herr promoted the idea at a 2017 TEDx event.
In March 2018, a €12 million pilot project to purchase 20,000-30,000 Global Passes for EU youth was confirmed by the European Commission. A press release announcing the decision elaborated on its goal of the scheme: "The action will seek to offer young people, regardless of social or educational background and including people with reduced mobility, a chance to travel abroad." On 1 March 2018, the European Commission announced initial steps to implement the European Parliament's proposal for a "Free Interrail pass for Europeans turning 18" by adopting a financing decision: "With a budget of EUR 12 million in 2018, this action is expected to give an estimated 20,000-30,000 young people a travel experience that would help foster a European identity, reinforce common European values and promote the discovery of European sites and cultures. This proposal fits well with the EU's ambitions to promote learning mobility, active citizenship, social inclusion and solidarity of all young people."
On 3 May 2018, Commissioner for Education, Culture, Youth and Sport Tibor Navracsics and Manfred Weber MEP announced that the initiative would be called DiscoverEU and outlined the first details on the application process. The initiative aims to give 15,000 young people the opportunity to travel around Europe during the summer to discover the continent's rich cultural heritage, get in touch with other people, learn from other cultures, and discover what unites Europe. Participants can travel up to 30 days and visit one to four foreign destinations. In an application round to select the first 15,000 travelers, those interested needed to apply during a two-week period in June 2018 through the European Youth Portal.