Transport for Wales said it had temporarily withdrawn a number of its Class 175 trains for additional maintenance checks after the issues.
The company, which runs a number of routes through Shropshire and Mid Wales, said that the disruption is likely to continue into early April.
It comes after more than 100 services were disrupted at the start of the month, due to three 'mechanical failures' on the Class 175 Trains.
Today there has been significant disruption throughout the county and Mid Wales, with a several trains cancelled.
The 12.29pm from Aberystwyth to Shrewsbury was cancelled, along with the 6.31pm train on the same route, as well as the return train at 6.33pm.
Transport for Wales said that services between Wolverhampton and Birmingham may also be cancelled as a result of the issues.
Customers are being asked to check before they travel.
Jan Chaudhry-Van der Velde, Chief Operations Officer at Transport for Wales, said: "The safety of our customers and colleagues remains our top priority.
"Our Class 175 trains will not be allowed into passenger service again until each train has had its engines checked and repaired, and has passed the relevant safety inspections. This programme of work is happening as we speak, at Chester depot, where these trains are maintained on our behalf by CAF Rail UK.
"An initial supply of materials is available for the repair programme, and further parts are being sourced from overseas to speed up the process. The position will improve each week, and the completion of the repair programme is expected to go into April.
"Whilst this leaves us with a temporary shortage of rolling stock, other fleets are being spread out across the Wales and Borders network, and timetables have been adjusted to try and impact the fewest number of passengers.
"We’re very sorry for the disruption to customers’ journeys while we carry out this essential work."