Besides the provision of a driver's cab on the CC version of the MP 89, another key difference between the CC and CA stock is the interconnecting gangways between trains. Most of the CC stock are equipped with reinforced gangways, which consists of solid interior panels. This was designed mainly due to fears that the curved platforms on Line 1 (such as Bastille), as well as storage of the trains within the tunnels, could cause significant damage to rubber gangways. However, some trains (#s 02, 08, 09, 13, 18, 51, and 52) have been fitted with rubber gangways since 2000, and six trains (#s 43, 45, 46, 48, 49, and 50) contain prototype gangways that were later implemented in the MF 01 stock "(from :fr:MP 89)". In 2012, train #12 was retrofitted with the MF 01 type gangways upon transfer of the train to Line 4, and in March, 2014, train #01 was retrofitted.