Line 8 of the Madrid Metro opened between Mar de Cristal and Campo de las Naciones (now Feria de Madrid) on 24 June 1998. An extension to Barajas via Madrid Airport was opened in 1999 and in 2002 an extension to Nuevos Ministerios and Colombia opened. Originally this line was a small-profile line, but in 2002 it became a large rolling stock line. The line uses 4-car versions of class 8000 trains. In 2007 an intermediate station called Pinar del Rey opened between Colombia and Mar de Cristal, as did an extension to the new Terminal 4 of Madrid Airport.