The report commissioned by the Federal Office of Transport said the move would help the Swiss rail network compete against the rise of long-distance buses and the ride-sharing service Uber.
The third-class carriages would have rows of seating for five people, according to the report, details of which were published in Swiss weekly NZZ am Sonntag.
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Their introduction would help meet the needs of different groups of passengers, the report’s authors said.
But the idea received a distinctly lukewarm reception from industry figures.
The director of Swiss public transport union VÖV, Ueli Stückelberger, said he agreed that operators should consider the needs of people with smaller budgets but argued the proposal for third-class travel would not mean more savings for passengers and would make the public transport system more complicated.
The SBB told the NZZ that third-class travel was not being considered at this stage.
The rail operator also noted it was currently making train travel more attractive for people on lower budgets with its supersaver tickets which offer discount off-peak fares.
Swiss trains had third class seating until 1956 but this was phased out because it was not financially viable, the NZZ reported.