The Spanish solution (also called Barcelona solution) has two railway platforms, one on each side of the line, to speed up boarding and alighting: passengers board from one side and alight to the other. If there are three platforms (one island platform and two side platforms) with two tracks, generally the center platform will be a shared exit platform, as there is no benefit in segregating arriving passengers. At most locations doors for exit open a few seconds before those for entry.
The solution was used in the United States in 1912 at Park Street Under on the MBTA's Red Line in Boston, and at Chambers Street on the New York City Subway in 1913, where the center platform is now closed.
On people movers at airports there are often dedicated platforms for boarding and alighting. This can have the additional advantage of preventing travellers heading in the wrong direction when alighting, and ensuring passenger segregation. The same principle is often used on ferries, monorails, and cable cars, fairground rides such as roller coasters, and in buildings such as theaters.
At a terminal station where trains are bi-directional (double ended) it is advantageous for the center platform to be for boarding and the side platforms to be for alighting. This permits an incoming train to enter on either track and remain in the station until it is ready to begin the next trip. Passengers boarding then do not have to know in advance which track the next train will depart from.
Sé on the São Paulo Metro is a recent example. Line 1 Blue (Linha 1 - Azul, Norte-Sul or North-South) uses this model at stations like Sé, a busy station due to Line 3 integration, and Line 3 - Red (Linha 3 - Vermelha, Leste-Oeste or East-West) uses this at Sé, Republic (Estação República), Itaquera, Barra Funda, and Luz.
In Hong Kong, the former KCRC (now part of MTR Corporation) reconstructed the platforms at the checkpoint terminus, Lo Wu, to a similar layout. When the train stops, the doors on the island (alighting) platform open and all passengers get off. Then the doors close and the doors on the side (boarding) platform open.
On the London Underground system, Loughton tube station was designed as an example, in this case to allow interconnection across the platforms with trains from beyond; though it is no longer operated on the principle.
- People's Republic of China
- Gongyuanqian and Xilang on the Guangzhou Metro.
- In Shanghai, the southbound Line 8 platform at People's Square doors open on both sides, but passengers enter only from the left, encouraging exit to the right.
- Luohu Station and Futian Checkpoint Station of Shenzhen Metro
- In the Beijing Subway, Xizhimen Station Line 13 platforms, Terminal 3 Station, Songjiazhuang Station Yizhuang Line platforms, and Haidian Wuluju Station.
- Beijing Capital International Airport Terminal 3 shuttle
- Ikebukuro Station on the Seibu Ikebukuro Line and Tōbu Tōjō Line
- Tōkyū Tōyoko Line terminus at Shibuya Station
- Keiō Line terminus at Shinjuku Station
- Odakyu Line terminus at Shinjuku Station
- Hong Kong
- Chhatrapati Shivaji Terminus
- First platform of Jogeshwari railway station.
- First platform of Kurla railway station.
- Olympic Park railway station, Sydney
- Skitube stations at Bullocks Flat and Perisher Valley
- Glanville, Brighton and Noarlunga Centre in Adelaide (one track only)
- Premetro tram stations between Brussels-South and Brussels-North on the North-South Brussels Metro, and Rogier on Line 2
- Jean Jaurès, on Toulouse Metro line B
- Hôtel de ville - Louis Pradel, on Lyon Metro line C
- Charles de Gaulle – Étoile, on Paris Métro Line 6
- S-Bahn: München Hauptbahnhof and Karlsplatz with island platform for boarding and side platforms for alighting, Marienplatz with eastbound track at upper level and westbound track at lower level - both have separate platforms for boarding and alighting.
- Stuttgart Stadtbahn: Pragsattel, Mineralbäder
- Barcelona Metro
- Glòries, Clot, Navas, Fabra i Puig, Sant Andreu on line 1.
- Catalunya, Muntaner, La Bonanova and Avinguda Tibidabo on lines 6 and 7.
- Old Santa Eulàlia station (line 1), Catalunya line 1 temporary station, La Sagrera (lines 1 and 5), Passeig de Gràcia (line 3), Diagonal (line 3) and Correos ghost station (line 4) used to have this configuration.
- Madrid Metro
- United Kingdom
- Tower Gateway station was rebuilt from a two-platform island terminus to a two-platform single-track terminus
- Gatwick Airport monorail shuttle between North and South terminals
- shuttle transit beneath A, B and C gates at London Heathrow Terminal 5
Stations where there are two platforms for one track, but passengers can board and alight from either side:
- Docklands Light Railway (DLR)
- Canary Wharf has six platforms serving three tracks.
- London Underground
- Barking - eastbound District line
- Stratford - westbound Central Line
- Golders Green - turnback (reversible) line. The northbound line could be used this way, but platform 1 is not available for public use.
- Morden - platforms 3 and 4 of the three-track terminus (platform 1 is out of use, with doors opening onto platform 2)
- Uxbridge and Cockfosters - three-track termini where the centre track shares platform islands with the outer tracks
- White City and Loughton - second and third platforms.
- National Rail
- Preserved Railways
- Toronto Subway and RT:
- GO Transit
- TransLink (Vancouver)
- United States
- Boston Park Street (MBTA station), lower level
- Stations in the New York City Subway are designed in the Spanish solution, but the side platforms at many of these stations have been closed:
- Wakefield – 241st Street
- Pelham Bay Park
- Van Cortlandt Park – 242nd Street
- 96th Street (local tracks only)
- 59th Street – Columbus Circle (express tracks only)
- 14th Street – Union Square (local tracks only)
- Brooklyn Bridge – City Hall (local tracks only)
- Chambers Street (easternmost three tracks only, formerly all tracks)
- Hoyt–Schermerhorn Streets (Fulton Street line express tracks only)
- Bowling Green (mainline tracks only; easternmost island platform has since been walled off to northbound trains, and westernmost island platform has since been closed)
Other stations, mainly express stations on three-track lines, have a Spanish solution for the middle track, but trains often open the doors on only one side, depending on the direction of travel. Two terminal stations that retain a Spanish solution are the R platforms at South Ferry - Whitehall Street, and Flushing – Main Street – the terminal for the 7 <7> trains, but the doors cannot open on both sides, due to constraints on newer rolling stocks.
- PATH tracks at Newark Penn Station in Newark, New Jersey has two out of three tracks using the Spanish solution, and 33rd Street in Manhattan has all three tracks using the Spanish solution.
- Stamford station in Stamford, Connecticut has two tracks that utilize the Spanish solution.
- Park Street Lower on the MBTA plus outbound Green Line C and E branch trains on Park Street's upper level and at Sullivan Square and Wellington on the Orange Line (both outbound only).
- Five Points, and Lindbergh Center (on northbound side) stations of the Atlanta MARTA.
- Epcot, Transportation and Ticket Center, and Magic Kingdom on the Walt Disney World Monorail System
- Long Island Rail Road - at Jamaica, three trains are often timed to arrive at tracks 1–3 and tracks 6–8, allowing passengers to walk through the center train to transfer between trains on the outer tracks. Ronkonkoma also uses a Spanish solution.
- White Plains Metro-North (outbound trains only)
- Pittsburgh International Airport People Movers
Tracks 1 and 4 in SEPTA's Suburban Station in Philadelphia, to Market East Station and beyond, contain what appears to be a Spanish solution, as those tracks share the (narrow) platforms which serve stub-end tracks 0 and 5 in addition to the wide platforms which serve through tracks 1-2 and 3-4. However, for logistical and safety reasons, this setup has seldom if ever been used; it is more of an artefact from when the platforms between tracks 1-2 and 3-4 were widened at the expense of two stub-end tracks to accommodate the Center City Commuter Connection which opened in 1984 (Market East, by comparison, has only two island platforms for its four tracks).
- Denver International Airport: the subway station underneath the Jeppesen Terminal is configured with passengers boarding from the central platform and alighting to the side platforms.
- Simón Bolívar commuter rail station in Caracas.