Replacement buses have been operating on the line since April 2021.
Trains only run once every two hours Monday to Saturday, instead 'supplemented' by replacement busses.
Operators have recently confirmed these busses will call at more locations, extending journey times. At the moment the train takes around 40 minutes from Nuneaton to Leamington, where as the bus takes twice as long at over an 1hr and 20 minutes depending on traffic.
West Midlands Railway said they are still feeling the effects of the pandemic, which has meant 1 in 3 members of staff missing work due to Covid.
It has also impacted the speed at which they can train new drivers and conductors.
A West Midlands Railway spokesperson said:
“We are fully committed to increasing the frequency of the train service between Nuneaton and Leamington Spa as soon as possible.
“The root cause of all performance issues on the line is a shortage of train crew, which we had begun addressing by recruiting additional staff before the pandemic struck.
“Unfortunately Covid-19 has had an unprecedented impact on our service with one-in-three colleagues missing work and 25,000 driver training days lost. This means it is taking much longer to train the drivers we need to run a full service.
“We have taken steps to make our training programmes Covid-secure and would like to reassure our passengers we will reinstate a full service when we are able to do so.”
Travellers have been growing increasingly frustrated at the lack of a full service, with one person taking to twitter to describe the situation as a 'farce'.