MR-63 Prototypes
In the early 1970s, the STM tested prototype chopper (hacheur de courant) traction systems on select MR-63 elements to improve efficiency and prepare for future designs like the MR-73. Two suppliers were evaluated: Hitachi and Jeumont (via Canron). The Jeumont system was ultimately selected and influenced the MR-73 fleet.
Jeumont Fleet (Elements 40, 41, 42)
[81-579, 80-040, 81-580] – Element 40
[81-581, 80-041, 81-582] – Element 41
[81-583, 80-042, 81-584] – Element 42
These elements were equipped with the Jeumont-Canron chopper prototype. Elements 41 and 42 returned to service around 2005–2006 as trailer cars (attached to standard motor cars), operating on the Green Line until retirement in 2016 2 years before the MR-63 phase-out, element 42 being the first before 41. Element 40 was more challenging to maintain due to unavailable spare parts for its chopper system; the project to return it to service was abandoned. It served as a parts source for Elements 41 and 42 before being retired earlier. One car from Element 40 (81-579) was sent to just for laugh's festival in 2008, and cambe back sitting behind STM's Youville shops, until it disapeared in around 2011, possibly scrapped.
Hitachi Fleet (Elements 10, 11, 12)
[81-519, 80-010, 81-520]
[81-521, 80-011, 81-522]
[81-523, 80-012, 81-524]
These elements received the Hitachi chopper prototype. The system produced a "one-note" motor sound and shared chopper components across cars. After testing (around the early 1970s), the japanese Hitachi choppers were removed and replaced with standard rheostatic traction systems by the mid-1970s, the default MR-63 motors. As the Jeumont design proved superior and was chosen for further development. Documentations, photos, are almost impossible to find, as they were reverted relatively quickly.
Legacy and Outcome
After several years, the STM acknowledged that these unique prototype elements did not fully fit regular network operations long-term. The Hitachi chopper was dismantled and replaced with default motors. These ex Hitachi elements were in service up until 2016-2018. Element 40 was never fully returned to service due to the difficulty in sourcing replacement parts for its chopper, it became a parts donor for Elements 41 and 42 to extend their usability. The Jeumont chopper prototype ultimately influenced the traction systems adopted on the entire MR-73 fleet, the dou-dou-dou you now hear on these trains. Rumours says that one of Element 42 jeumont motors was kept, but this is not confirmed. If you have any photos, documents, regarding this, please let us know.