because of the tight curvatures in the Sierra Morena (occasionally dipping as low as ). According to the HS2 website, a track needs a curvature of and a track needs a curvature of . As the necessary curvature increases in proportion to the square of the maximum velocity, the maximum safe speed for a curvature of would be , assuming no tilting technology: - only the AVE Class 100, AVE Class 102 and AVE Class 103 run through the Sierra Morena section, of which only the AVE Class 102 has tilting technology. The trains travel at a top speed of between Córdoba and Seville, possibly on account of the AVANT services that also use the line, whose trains are limited to . On most journeys, the trains spend a very small proportion of the journey travelling above , although most of the Málaga branch is done at (save for station approaches and the Gobantes and Abdalajís tunnels). The trains slow down to approximately when travelling through Ciudad Real station. They also have to slow down to when travelling through Puertollano station because of the lack of a bypass route and tight curvatures in the station. History On 11 October 1986 the Spanish government decided to build a new railway between Madrid and Seville. On 25 February 1988, the international tender for the acquisition of 24 high-speed trains AVE followed; these trains were ordered by 23 December 1988. The first train, based on the third generation of TGVs, was delivered on 10 October 1991. In December 1988 it was decided to build the new line in standard gauge. Construction was ordered on 16 March 1989, and it lasted for 33 months; actual construction activity lasted only 24 months. Commercial use of the line commenced on 21 April 1992. In the first weeks, over 23 thousand passengers used the new trains - an occupancy rate of 81%. On 20 April 1992, services started between Madrid and Seville. Non-stop travel time between the two cities were 2:45 hrs; with stops at Ciudad Real, Puertollano and Córdoba it was 2:55 hrs. In 1992, tickets cost around 50-70 euros in second class, in first class over 100 euros. In 2014, a new station was added in Villanueva de Córdoba, between Córdoba and Puertollano, to improve accessibility of the Los Pedroches region. The line later received branches in Andalusia. In October 2015 an extension of the