Tram drivers in Nottingham will not receive bonuses this year - and have been offered turkey rolls instead.
The GMB union said Nottingham Express Transit (NET) staff were usually given a £25 shopping voucher at Christmas.
But this year drivers have been offered a free roll or baked potato from a food van parked outside its city depot.
NET said it had thanked staff for their efforts throughout the year and an additional bonus would be "inappropriate".
Sarah Worth, GMB regional organiser, said the union had not been made aware of the change in advance.
She said: "It's not the monetary element staff are aggrieved about as such, it's the way it's been done and the lack of acknowledgement.
"NET say they have told staff that their efforts are appreciated but the feedback I've had from members is that's not true.
"The bonus is a gesture that staff appreciate as a thank you from your employer and it makes you feel valued, appreciated and ready to come back the following year.
"These are front-line staff in customer-facing roles."
Ms Worth added about half of the staff would not even get the free snack due to not being at the depot when the food truck was parked there.
A NET spokesman said: "Throughout the year, our employees have done a fantastic job in maintaining a vital service and we've frequently and consistently expressed our gratitude for all their efforts through various internal communications channels.
"The past year has been difficult for everyone, and through the pandemic we've seen a significant reduction in customer numbers as the travelling public followed government advice to avoid public transport.
"It would, therefore, have been inappropriate to provide additional bonuses for employees at this time."