People commuting between Longueuil and Montreal may run into some snags in trying to cross over the St. Lawrence River this weekend — and for the next 12 weekends, too.

The yellow line of the Montreal Metro will be down every Saturday and Sunday from March 8 until May 25 as workers make repairs to the vaulted ceiling in the tunnel between Berri-UQAM and Longueuil stations.

The line will also be closed on the weekends between September and December, but will operate normally during the summer months, for a total 25 weekends this year.

Three shuttle buses will be deployed to make the run between Longueuil and Montreal:

804 Longueuil - Papineau - Berri-UQAM

  • Saturdays: 5:30 a.m. to 1:30 a.m.
  • Sundays: 5:30 a.m. to 1 a.m.

820 Longueuil - Jean-Drapeau

  • Saturdays: 5:30 a.m. to 1:30 a.m.
  • Sundays: 5:30 a.m. to 1 a.m.

877 Berri-UQAM - Papineau - Jean-Drapeau

  • Saturdays: 5:30 a.m. to 1:30 a.m.
  • Sundays: 5:30 a.m. to 1 a.m.

According to the STM, groundwater has seeped into the concrete and through the tunnel roof, causing damage.

The STM said it will also add drainage ducts to the vaulted ceiling, as well as perform electrical work.

"These repairs are needed to keep our infrastructure in good working condition and ensure the reliability of our network. Although the safety of transit users is not at all at issue, if we want to act responsibly, we must carry out this work in 2014," said Carl Desrosiers, STM's chief executive officer, back in December when the work was announced.