The double deck carriages date to at least as early as the second half of the 19th century. France several hundred voitures à impériale with seats on the roof were in use by the Chemins de fer de l'Ouest, Chemins de fer de l'Est and Chemins de fer du Nord by 1870, having been in use for over 2 decades; the design was open at the sides with a light roof or awning covering the seats.
They were used for the double-decker carriages, wherever feasible, and can resolve capacity problems on a railway, avoiding other options which have an associated infrastructure cost such as longer trains (which in turn require longer station platforms), more trains per hour (which the signalling or safety requirements may not allow) or adding extra tracks besides the existing line.
In the 1860s M.J.B. Vidard introduced two-storied carriages on the Chemins de fer de l'Est, with a full body, windows, and doors; the same design lowered the floor of the lower storey to keep the center of gravity low.
A bilevel car may carry about twice as many as a normal car, without requiring double the weight to pull or material to build. However, a bilevel train may take longer to exchange passengers at each station, since more people will enter and exit from each car.
The Bilevel cars may not be usable in countries or older railway systems with low loading gauges This includes much of the rail network in the northeast of the USA and almost the entire British rail network.
In some countries such as the UK, new lines are built to a higher loading gauge to allow the use of double-deck trains in future.
Today these rail cars are still in use.
- The Bilevel trains are claimed to be more energy efficient, and may have a lower operating cost per passenger.
- The Bilevel cars may not be usable in countries or older railway systems with low loading gauges.
- In India, the Flying Ranee, a passenger train between Surat and Mumbai Central on the Western Railway uses double-deck cars, since the 1970's.
- These cars are seen in many places the world over like Argentina, Australia, Canada, China, Denmark, Finland, France, Hong Kong, India, Israel, Italy, Japan, Russia, Slovakia, Sweden, Switzerland, the Ukraine, the United Kingdom and the United States.
- These cars are also used on long-distance trains in the Northeastern United States and Quebec, as well as California, Florida, Illinois, New Mexico, to name but a few.
- Bilevel cars may not be usable in countries or older railway systems with low loading gauges.
- The first bilevel train for China Railways was built by Sifang in 1958 as Dongfeng diesel multiple unit, consisting of two locomotives and four bilevel coaches.
- In 1964, Tulloch Limited built the first double-decker trailer cars for use in Sydney.
- The Chicago, Burlington and Quincy Railroad placed bilevel cars in commuter service in the Chicago area in 1950.
- In Denmark, DSB began running Bombardier Double-deck Coaches in 2002. The coaches are used on Regional services on Zealand.
- In each of these agencies' bilevel cars, two levels are present between the trucks of the car.
- The New Mexico Rail Runner Express utilizes bilevel cars on its route from Santa Fe, New Mexico to Belen, New Mexico.
- When they are use for the Altamont Corridor Express, Caltrain, Coaster, FrontRunner, GO Transit, Metrolink, Northstar Line, Rail Runner Express, Sounder, SunRail, Tri-Rail, Trinity Railway Express, West Coast Express, and Exo they are called "Bombardier BiLevel Coach" they are bilevel passenger railcar designed to carry up to 360 passengers for commuter railways. These carriages are easily identifiable; they are double-decked and are shaped like elongated octagons.
- Southeast Florida's Tri-Rail service between Miami and West Palm Beach uses Bombardier bi-level coaches similar to those of Toronto's GO Transit.
- Canada's national intercity passenger railway company, Via Rail, does not currently operate any bilevel cars in its rolling stock fleet although during the late 1980s and early 1990s it had examined purchasing Superliner II equipment; this did not occur as the company endured a significant budget cut in 1990 and opted to instead rebuild the former Canadian Pacific Railway stainless steel passenger car fleet produced by the Budd Company.