The line was completely blocked at one point on Wednesday, with a train travelling in each direction held up.
Customers stuck at stations waiting for their train took to Twitter to ask West Midlands Railway staff what the delays were for.
Through the day West Midlands Trains announced on its website that, because of a safety inspection of the track between Wolverhampton and Telford Central, trains were having to run at reduced speed on all lines.
It said that would impact on any of the train services running through those stations.
"The trains may be cancelled or delayed by up to 60 minutes and disruption is expected to last until around 6pm," the train operator said.
It said that it expected some of the trains to be affected by the safety inspection.
At about 4pm West Midlands Trains tweeted that there had been problems reported.
"There are cancellations to services between Wolverhampton and Telford Central. Due to a safety inspection of the track between Wolverhampton and Telford Central all lines are blocked," a spokesman said.
They added that an incident had been reported and railway teams were close by.
"It is currently affecting two trains - one in each direction."
The problem led to delays of around 25 minutes and West Midlands Trains said that some trains were terminating early.
It was hoped that services would return to normal by 6pm.