@Maersk.146 Thank you! I’ll try to explain my best. In 1980 RENFE, Spanish public operator, decided to modernize its diesel shunting locomotives fleet. The 309 series was the first result of this renewal but a more powerful shunters were needed, that’s why in 1982 RENFE helped by PID plan and CEDETI (Industrial and Technical Development Center) decided to build a prototype for this new shunting locomotives. The prototype was numbered as 311.001 and it was known as MABI though the builders that took part in this project: M (MTM) A (Ateinsa) B (Babcock & Wilcox) I (INI - National Industrial College). In 1990 the 311.1 series production started. It was so similar to 311.0 prototype only with little changes, that’s why Spanish trainspotters adopted de nickname “MABI” to call 311.1 series locomotives.
@Iñigo I like that! Thank you very much for the information. We spotters certainly do like knowing things about rail equipment. It seems amazing that our wives and girlfriends do not always share our keen interest in such important knowledge and details...