The first FV-Dosto double-decker express trainset to have its tilt system removed has returned to revenue service in Switzerland, marking a concrete step in the reconfiguration of one of the country's most technically troubled fleets.

The FV-Dosto fleet, operated by Swiss Federal Railways (SBB), has been shaped by years of problems with its electric-hydraulic tilting equipment. The decision to strip the tilt system from part of the fleet converts the trainsets from tilting to conventional fixed-body operation on intercity routes.

What does the change mean for operations?

Removing the tilt hardware eliminates the technology that repeatedly caused availability problems, but it also caps curve speeds at conventional levels. On SBB's winding intercity corridors, tilting trains were procured specifically to cut journey times without building new track. A de-tilted FV-Dosto therefore runs slower through curves than the design specification intended.

For SBB, the trade-off is operational reliability against timetable performance. A trainset that runs reliably at conventional speeds can be worth more to the operator than one that promises faster runs but spends extended periods out of service for tilt-system repairs.

Why did SBB take the tilt system out?

The FV-Dosto programme has a long record of technical setbacks since the trainsets entered service. The tilting equipment was a persistent source of faults, delays and maintenance burdens. Rather than continue repairing a system that undermined fleet availability, SBB opted to remove it from trainsets and operate them as conventional double-deckers.

The return to service of the first converted unit gives the operator its first hard evidence of how the modified trainsets perform in daily traffic — data that will govern the pace of further conversions across the fleet.

What happens next?

SBB now faces a scheduling question. Timetables built around tilting-train running times must absorb the slower profile of fixed-body FV-Dosto sets, or the operator must deploy the converted units on corridors where the speed penalty is smallest.

The performance of this first de-tilted trainset over the coming months will determine whether SBB accelerates the conversion of the remaining tilt-equipped units or adjusts its approach — the milestone in Switzerland is the start of that measurement, not the end of the fleet's restructuring.