The Stakes of the Tram Infrastructures Renewal in the Metropole of Nantes

The Stakes of the Tram Infrastructures Renewal in the Metropole of Nantes




30 years after the redeveloppment of the tram in Nantes, the public transport authority faces infrastructures renewal issues. The paper presents the way Nantes drives its projects, and gives a current example of renewal in the center of the city.


Nantes, with its 600 000 inhabitants, was the first metropole in France to developp a new form of tram in the 20th century. A large part of its present tram network celebrated its 30th birthday in 2015. It now represents 44 km of infrastructure and 91 trams. Each tram runs 60 000 km/year and the tram network is used by 290 000 people/day. These figures show how impacting could be a breakdown in the network for the users in their every-day mobility : thousands of people might instantly suffer from it.

This leads to a big responsibility for Nantes Metropole in the fields of maintenance and renewal, for the trams themselves, and of course for the infrastructure. Our paper aims to present how the public metropole and the semi-public society that operates the network (the SEMITAN) do to plan and operate these crucial operations, in order to maintain and modernise the network, and also to make sure that it keeps being safe for everybody and accessible for those with impaired mobility. In France and especially for “ancient” networks like Nantes' one, renewing and maintaining issues can represent more than the half of the public transport investments every year and this proportion will surely increase in the further decades if networks authorities want to keep the present high level of service for users. That is why the Nantes' case can interess all the urban districts in France and Europe that face or will face theses issues in the future.

First we will explain the type of organisation that was chosen in Nantes to carry out successfully the maintenance and renewal operations. We will detail the way the process is conducted between the public transport autority and the operator, from the diagnosis to the accomplishment, including the way the detailed planning is done. The majority of the big infrastructure renewal operations are conducted by the SEMITAN in the framework of the public service delegation contract. Planning the renewal operations needs to be anticipated and cannot be only decided on the bases of what would be the best for the infrastructure : it needs a detailed work with all the stakeolders, which has to take into consideration many different variables. One of them is the global budget situation of the metropole. The public transport is indeed the field of Nantes Metropole's jurisdiction which weighs the biggest amount of investments. Therefore, financial studies largely contribute in the definition of the long term intervention planning, as does the political agenda. Another variable lies in the synchronisation between tram renewal and urban redevelopment projects, which Nantes Metropole tries to achieve. And last but not least we can quote the disagreements for the tram lines that happen during the infrastructure renewal worksite : one cannot cut the network for a month or two without offering people a substitute to complete their travels.

Then we will developp one precise example : the renewal of the heart of the tram infrastructure of the city of Nantes, which is planned with at least three large renewal operations for a cost of almost 30 millions euros for the next five years, in accordance with urban planning also. It will begin in the summer of 2016 a 500 m long tram lane will be renewed. The operation cost of 8 millions euros could be considered as very expensive. We will show that the metropole made the choice to seize the opportunity of the renewal in order to also modernise this part of the network : the railway is changed and in the meantime new equipments are developped to guaranty a better security and accessibility, and to improve the operationability of the tram lines. From the political decision to carry out this renewal to its accomplishment, more than two years passed. We will detail the project management that was built for the operation, and tackle the major advantages and inconvenients for each step of the project. This example will enable us to fully understand the renewal projects' mechanisms, that have to be improved every time so that the public transport authority can hold to its strategic role and in the meantime make sure some important details are well taken care of.


Association for European Transport