Eurostar

Eurostar - London to Paris
The Eurostar is a high-speed express train connecting the UK with Europe. Travellers can get to a variety of major cities directly including Brussels, Amsterdam, Rotterdam and Marseille, although its most popular route is London to Paris taking approximately 2 hours 15 minutes. Wifi is currently available on all e320 trains and is planned to be rolled out across all trains along the route.
Available classes
The Eurostar offers both Eurostar standard and Eurostar standard premier which are the equivelent of first and second class.
Eurostar standard: Will get you a seat on the train and access to other amenities such as wifi if available.
Eurostar standard premier: Will get you everything in standard class in addition to a free meal, more space and accessible power sockets.
Paris - Moscow Express
The most luxurious way to travel to Russia from Paris or the UK, the Paris - Moscow Express was built by Siemans in 2014 and has been kitted out with many features and facilities that make the 2164 mile-long train journey as comfortable as it can be. The train consists of 4-berth, 2-berth and single occupancy cabins with modern air conditoning, carpeted floors, a wash area and toliet at the end of the carriage and on-board attendents that can help you with just about anything you need.
Available classes
The Paris - Moscow Express offers 3 classes: second class, first class and business class.
Second class: Provides a bed in a shared 4-berth sleeper cabin.
First class: Provides a bed in a shared 2-berth sleeper cabin.
Business / VIP class: Can be either a shared luxury 2-berth sleeper or a sole occupancy cabin. Each comes with a sofa that converts into an extra wide berth at night, while an upper berth folds out of the wall. The compartment also comes with an en-suite shower and toilet as well as a CD player and flatscreen TV.
Berlin - Warsaw EuroCity train

Berlin - Warsaw EuroCity Train
kaffeeeinstein / CC BY-SA (https://creativecommons.org/licenses/by-sa/2.0)
Three EuroCity trains link Berlin with Warsaw every day, taking approximately 5 hours and 30 minutes to make the 356-mile journey. The train typically comprises of several second class carriages which are visually marked with a green stripe outside the train and one first class carriage marked in yellow. All trains have air conditioning and a restaurant car.
Available classes
Berlin - Warsaw EuroCity trains have two classes available: second class and first class.
Second class: Includes a reserved seat.
First class: Includes a reserved seat with additional space.
Warsaw to Moscow sleeper train

Russian Railways Train
Owned by Russian Railways, the Warsaw - Moscow sleeper train comprises of a variety of 4-berth, 2-berth and single berth compartments and a toilet / washroom at the end of each corridor.
Available classes
The Warsaw - Moscow Sleeper train has two classes: second and first class which comprise of 4-berth, 2-berth and single berth compartments.
Second class: Includes a bed in a shared 4-berth compartment
First class: Includes a bed in either a 2-berth or single berth compartment offering more space and privacy.