Concept proposal · Opening 2040
A metro line beneath the Tagus.
Cais do Sodré and Cacilhas three minutes apart, at any hour, in any weather. A 2.3 km link under the river, designed for Lisbon and Almada.
See the route Engineering detail
The river is the metropolitan area’s biggest barrier
To cross between Almada and Lisbon there are three options: the ferry, the bridge, or the train over the bridge. The Cacilhas ferry takes about 10 min7 on the water, but only leaves every 15–20 min7, and waiting time counts. The 25 de Abril Bridge is congested every day.
The Cacilhas–Cais do Sodré route is the busiest of the electric ferry fleet: 52 %8 of the new vessels’ passengers. The demand is there; what’s missing is a frequent, reliable link.
The idea
Two metro tunnels bored beneath the riverbed, between a new station at Cais do Sodré and another at Cacilhas. No works in the river, no interruption to the ferries, linked to the metro, the Cascais railway, Metro Sul do Tejo and buses.
A train every three minutes at opening, with room to grow to one every two.
In numbers
Design values. Estimates are labelled; real data is sourced.
A trip in 2040
- 07:52Corroios
Ana takes the Metro Sul do Tejo tram to Cacilhas.
- 08:09Cacilhas
She steps off the tram and, across the same covered square, enters the station, going down to the platform with daylight from the light well.
- 08:11Under the Tagus
The train passes almost 60 m below sea level. Three minutes later she is in Lisbon.
- 08:15Cais do Sodré
She changes to the Green Line or the Cascais train without going outside.
Illustrative scenario.
The project dossier
Route & stations
Where it runs, where the stations are and how it links to the network.
SHEET 03Engineering
Geology, profile, TBMs, typical section, earthquake design and safety.
SHEET 04Architecture
Stations with daylight, simple wayfinding and step-free access.
SHEET 05Environment & heritage
No works in the river, spoil by barge, archaeology watched.
SHEET 06Cost, schedule & ridership
Programme to 2040, estimated cost, demand and risks.
SHEET 07FAQ
The most common questions, in plain language.