Both of the region's operators, West Midlands Railway and Transport for Wales, have warned passengers to expect disruption ahead of Christmas and throughout the festive period.
The situation is largely down to a major rise in Covid cases, caused by the more transmissible Omicron variant.
Transport for Wales, which operates trains from Mid Wales to Birmingham, through Shrewsbury, Telford, and Shifnal, has already confirmed an 'emergency timetable' to start from today, while West Midlands Railway warned "some services may be cancelled".
The Transport for Wales emergency timetable is expected to see up to 15 per cent of services removed.
There was already frustration from some passengers at Shrewsbury Railway Station, with concerns that the situation would make the service worse than it is.
Matt Herbert, 54, from Shrewsbury, who uses the trains to travel to work in Aberdeen, said: "There's always a delay or replacement buses.
"Even if I'm just going to Telford there is always disruption. I've never known anything like the train services at the moment – it's worse than a third world country."
Both rail operators said passengers should check before travelling throughout the festive period.
A spokesman for West Midlands Railway said: “Like many industries, we are currently experiencing an increase in staff absence and self-isolation requirements due to the pandemic.
“While we are covering as many services as possible using overtime, staff shortages may mean fewer trains are able to run and as a result some services may be cancelled.
“We apologise to passengers impacted by this issue and advise all customers to check their journeys before travelling.”
Colin Lea, planning and performance director at Transport for Wales said: “We are still very much dealing with a pandemic and have seen a major rise in colleague absences over the last few weeks.
"Since the beginning of December, the number of rail colleagues absent due to Covid-19 has doubled and this will continue to rise with the ongoing risk of the new Omicron variant.
“It’s fundamental we continue to run as reliable a service as possible for our customers and therefore we are introducing a new timetable from today, reducing the risk of late notice cancellations."