Geneva public transport workers are planning to strike on Wednesday 12 October. Unions are demanding a pay rise which is linked to inflation.
The company has already agreed to a rise of 0.6% and a one-off bonus of CHF 400.
But workers are calling for 1.2%, back-dated to the start of the year.
Talks over the summer have failed to reach an agreement.
The TPG has recently made a loss due to the pandemic and says its offer is reasonable given the circumstances.