References

Within the framework of its development by 2015/2020, EPAD required an additional railway service. The idea of using EOLE is not new, as the original plan was to extend the current St Lazare Condorcet terminal to the group II railway network: La Défense then Versailles (RG).
However, EPAD, aware of current congestion of the St Lazare station, requires an effective service, which gave rise to the idea of a St Lazare / La Défense tunnel. The next question was: where to build a 220m long station, and a tunnel between the Pont de Neuilly and the Arche de La Défense. The programme also plans to link EOLE tracks to group V (to Mantes) via the La Folie freight station.
The idea appeared of reusing the old precautionary measures for line 1 constructed in the seventies, and not used in the actual extension of this line 20 years later. However, the feasibility of this operation had to be checked: it consisted in making a RER train go through a metro tunnel ! The nature of the precautionary measures is highly variable, there is a large room below level -4 of the parking lot of the shopping mall (old line 1 station); there is also the upper slab and diaphragm walls which were to be used to build another station; the future ventilation shaft can be seen from groundlevel. Many towers had their foundations moved to give way for the Metro reservation…

An extension to Mantes in the long term
The Mantes/La Défense link is also planned. The site of La Folie in Nanterre must be used to build a station.

High constraints due to existing structures
The main part of the mission consisted in retrieving from EPAD archives all the precautionary measures accumulated over time, transfering them onto a reliable drawing, and trying to find a route for a RER line using those areas.

Terrasol’s achievements: