>>1300554Basically the whole thing was the final time RATP built a prototype. It was an ambitious idea: using the 7bis line as a testbed. That line is still today an absolute joke that hardly justifies heavy rail. It was a former branch of the 7 line that got separated from it and operated independently since 1967 and hasn't really evolved since then. Operates on a 5 min headway during the day.
So 1988, the RATP goes ahead with a tender for nine 3-cars sets with everything they validated on the previous one off prototype (the Boa, which was an extremely modified MF77 set), including walkthrough design, more extensive onboard computer logic (which eventually paved the way towards the first automated line), weird ass 2 self-steering axles with a diff and other things.
The axles were a mistake. A big one. They were great for reducing screeching in tight curves (this is why the 7bis was chosen as testbed over the even shorter and more useless 3bis) but absolutely trashed the rails, and were far more expensive to operate and maintain than traditional bogies.
So out goes the MF88 plan. At this point RATP throws everything it learnt from it into the automated line 14 and MP89 rolling stock. It had to wait until 1998 to have the resources to issue a tender for a new steel-wheeled rolling stock, which would by the time it got delivered and introduced into revenue service (2008) allowed the beginning of the MF67 retirement.
Today they still run the 7bis because no one really wants the old screechers back, so RATP keeps them running until they eventually break (cannibalization started ca. 2010, 1 down, 8 to go), and if that happens before 2025 (more likely 2028-2030)... Well the line which saw the failure of the MF67 successor would be operated by MF67s again.
