Sheet 06 · Programme

Cost, schedule & ridership

What it costs, how long it takes, who will use it, and what could go wrong.

Project
TT-CS-CC
Sheet
06
Rev.
A
Date
2026-11
Reading level
Summary for everyone; Technical for engineers and architects.

01Programme to 2040

Programme to opening in 2040Studies, financing & governance: 2027–2029; Surveys, EIA, public consultation, reference design: 2029–2031; Procurement; early TBM order: 2031–2033; Enabling works, archaeology, shafts: 2033–2034; Tunnelling and station structures: 2034–2037; Fit-out, systems, testing & certification: 2037–2039; Programme float: 2039–2040202720292031203320352037203920402041Studies, financing & governanceSurveys, EIA, public consultation, reference designProcurement; early TBM orderEnabling works, archaeology, shaftsTunnelling and station structuresFit-out, systems, testing & certificationProgramme floatOpening 2040
Indicative programme, with 12 months of float before opening.TT-CS-CC-06-PG

Opening is targeted for 2040 Estimate. Most of the years until then are studies, permitting and procurement; construction itself takes about six years.

  • TBMs take 2–3 years to build: the early order (2031–2033) overlaps the civil works tender so it stays off the critical path.
  • Critical path: EIA → procurement → Cacilhas shaft → tunnelling → fit-out → testing.
  • Programme float: 12 months (2039–2040).

02Cost

The estimated cost is 1.9 € bn Estimate at 2026 prices, within a range of €1.6–2.3 bn. It includes a margin of about 25% for risk, usual at this stage of study.

Cost breakdown (€ bn, 2026 prices)
ItemValue
Twin tunnels (2 × 2.3 km)0.70 Estimate
Two deep stations0.45 Estimate
Systems, track, signalling, rolling stock and depot0.29 Estimate
Design, land and supervision0.10 Estimate
Subtotal1.54 Estimate
Risk contingency (~25%)0.39 Estimate
Total1.93 Estimate

Basis: unit costs for urban river-crossing tunnels (~€0.3 bn/km per pair of bores) and deep stations in soft ground. Excludes VAT, future inflation and financing costs. Possible funding: State Budget, EU cohesion funds and the CEF facility, and the European Investment Bank.

03Ridership

We forecast about 75,000 passengers a day Estimate in 2045. For comparison, the whole Lisbon metro network carried 176,727,28410 passengers in 2024.

For today’s ferry users, the average saving is about 13 minutes per trip Estimate: a shorter crossing and much less waiting.

Sources of forecast demand (2045)
SegmentPassengers/day
Current Cacilhas–Cais do Sodré ferry users≈ 15,000 Estimate
Shift from the 25 de Abril bridge corridor (car and bus)≈ 35,000 Estimate
Metro Sul do Tejo feeder trips and induced demand≈ 25,000 Estimate
  • Journey time: ferry (10 min7) + average wait ≈ 8 min (departures every 15–20 min7); metro 3 min Estimate + average wait ≈ 1.5 min.
  • Peak-hour load ≈ 9,000 pphpd Estimate against an opening capacity of 20,000 pphpd Estimate: headroom for growth without new works.
  • The shift from the bridge corridor is the weakest estimate: it has no published source and depends on fares, parking and Metro Sul do Tejo service. The 60–90k passengers-a-day range mostly reflects this uncertainty.
  • Forecast to be refined with the metropolitan demand model in the study phase (2027–2029).

04Comparable projects

Reference underwater crossings
ProjectTypeLengthNotes
Marmaray (Istambul)Immersed rail tube1,387 m18Down to ~60 m18 below sea level, in a seismic zone
Fehmarnbelt (DK–DE)Immersed road-rail tube17.6 km19Budget 7.4 € bn19 (2015 prices)
Øresund (DK–SE)Immersed road-rail tube4 km20Part of a bridge–island–tunnel link
Túnel do TejoTwin bored metro tunnels2,300 m Estimate1.9 € bn Estimate

Indicative comparison: the projects differ in type, length, use and date, and cost per kilometre is not directly comparable.

05Programme risks

Schedule risks and effect on float
RiskPossible delayMitigation
EIA delay or challenge9 months EstimateEarly consultation and well-documented alternatives
Adverse ground conditions6 months EstimateExtensive ground investigation; mixed-face TBM
Failed or challenged tender6 months EstimateEarly market engagement; balanced lots
Archaeological finds4 months EstimateSurvey in 2033–2034, before the walls

Risk-adjusted range

If all of the risks above occurred together (25 months), the 12-month float would not be enough. So we state an honest range: opening in 2040 in the central case (P50) and by late 2041 in the adverse case (P90).