Last week, the RMT called off strikes planned for 22, 23 and 29 December to consider Avanti’s new offer.
But the union said late on Tuesday that 83% of the 400 members involved in the dispute voted against the deal.
The revised offer included higher rest day working payments and more organised allocation of shifts on rest days, it said.
Train managers usually work a 41-hour week but due to staff shortages can be asked to work on their days off. The RMT has argued the current arrangements are “unacceptable”.
Avanti said in response to the latest strikes being announced that it was “disappointed” by the vote against a “very reasonable” revised offer.
“This strike action will cause significant disruption to our customers making journeys on the West Coast Main Line over an extended period,” a statement said.
“We remain open to working with the RMT to resolve the dispute.”
It said it was looking at how the strikes would impact services and would confirm its plans as soon as possible.
Since the middle of 2022, rail travel has been disrupted by industrial action as the RMT and the train drivers’ union Aslef sought better pay and conditions for their members.
The previous Conservative government said changes to working practices were required in return, but Labour secured a deal with the unions after winning the general election.