The public display for the Mattertal Tunnel closes today, 29 September 2026. Matterhorn Gotthard Bahn (MGBahn) submitted the plan-approval project to the Federal Office of Transport (BAV) on 30 June. Under the proposal, the line between Täsch and Zermatt leaves the valley floor and moves into the mountain. It would run about 4.1 km of single track, with a 1.4 km double-track passing section inside the rock and a parallel safety gallery linked to the main tube every 500 m. Four of those cross-passages hold technical rooms for railway equipment. The estimated cost is CHF 470 million. MGBahn states that keeping the existing route, which is exposed to avalanches and rockfall, safe would cost about CHF 220 million on its own.

For me, the key figure is the ratio between those two numbers: protection alone costs 47% of replacement. Once managing a hazard costs about half as much as leaving it behind, relocation stops being the luxury option. For an asset meant to run for a century, it becomes the rational one.

What the rock is

The ground is described in the project reference from Rothpletz, Lienhard + Cie, part of the planning consortium IG Horu. The north is mostly gneiss and the south mostly Bündner schist. Between them lie Triassic zones of dolomitic and calcareous marble and rauhwacke. Near the portals the ground turns to debris and moraine. At Täsch, the line reaches the portal over a new bridge across the Vispa. At Zermatt, the works include replacing the Schafgraben protection gallery. An access gallery comes in from the Grüebe area. Most people who ride through the tunnel from 2035 will never know the names of the engineers who logged every change in the rock.

The operational gain shows up in the timetable. Täsch–Zermatt drops from 12 minutes to about 6–7. The shuttle moves from a 20-minute to a 15-minute Takt, with half-hourly Visp–Zermatt service on top, and the line can run 365 days a year. Today it carries up to 200 trains a day and more than 4.4 million passengers a year. Zermatt is car-free, so for most visitors the Täsch shuttle is the only way in.

Why now

The reason is on record. In June 2024, storms and debris flows sent the Mattervispa and the Triftbach over their banks. Rail and road both closed for more than 24 hours, and Zermatt was cut off. As swissinfo reported at the time, Täsch–Zermatt reopened quickly, but Visp–Täsch stayed interrupted until mid-August. The full line reopened on 26 August 2024. Much of that recovery was done by maintenance crews that no timetable ever credits. MGBahn says the valley route now sees operational interruptions every year.

In the MGBahn release of 1 July 2026, Zermatt’s Gemeindepräsidentin Romy Biner-Hauser says the past has shown that safe, year-round rail access is needed, and that the tunnel is crucial for Zermatt’s secure accessibility. Manuel Juon, MGBahn’s head of infrastructure, calls it a Jahrhundertprojekt, a century project that raises operational safety and accessibility. In mid-June the Federal Council named it a key project with regional impact. Funding from the Railway Infrastructure Fund (BIF) under STEP is secured, provided Parliament agrees.

←TODAY: CHF 220M to protect the valley line, or CHF 470M to take it into gneiss and schist. The objection window closes today. →3012: the lines still running are the ones that were moved out of the hazard’s way before it came back. Fulcrum: a protection budget is also a price signal, and past a certain ratio it is telling you to relocate.

The trade-off, plainly: the tunnel does not arrive until 2035. Main excavation starts in October 2029 and breakthrough is planned for September 2031. That leaves about nine more winters on the exposed surface route, so some protection spending continues during construction.

Atelier: Any office working on an exposed asset will eventually face the same choice between protecting and relocating. That could be a hut access road, a Valais hotel annex or a hydropower access route. The choice usually gets made in fragments, one net or gallery at a time. Monday move: put it on one page. In one column, list the cantonal hazard map (Gefahrenkarte) zone and the protection capex. In the other, list the relocation capex. Put availability days per year and design life beside both.

Hack: Turn MGBahn’s two published figures into the ratio and the yearly premium your client actually has to decide on. The code runs in any Python, including the GhPython component in Rhino + Grasshopper. Design life is your own assumption. There is no discounting, because this is a first page, not a full business case.

protect, relocate = 220e6, 470e6   # CHF, MGBahn release
life = 100                         # years, assumed design life
print(f"ratio {protect/relocate:.0%}")                  # 47%
print(f"premium CHF/yr {(relocate-protect)/life:,.0f}")   # 2,500,000

About CHF 2.5 million a year buys a line that no longer closes for debris flows. Set that against one day in which a car-free village cannot move. In Grasshopper, load the alignment as a curve and overlay the hazard zones as closed polygons. Then measure the track length inside each zone. That length drives your protection capex.

Read the Auflage documents while they are still posted. Then ask your own client: what does keeping the old route alive cost, as a percentage of replacing it?