There were 12 fire crews at the station after the fire broke out at the rear carriage of an Arriva Trains Wales service.
Video courtesy of Barry Jones
The blaze started at 10.48am this morning and the station was evacuated and closed which caused long delays and cancellations on the line.
Fire station manager Pete Hawkins said there were people in the carriage when flames came from underneath it, but confirmed there were no casualties.
He said: "There were flames coming from underneath the carriage, and there were people on it, the train had just arrived in the station.
"There was a full evacuation put in place prior to our arrival. There were no casualties.
"We used one hose reel jet to extinguish the fire once it was isolated from the alternator.
"The crews remained at the scene cooling the train before they opened the station to the public."
The station was reopened shortly after 12pm.
Routes affected included Shrewsbury to Birmingham New Street, Crewe, Chester, Aberystwyth and Hereford. Disruption is likely to continue throughtout today.
A spokesman for the British Transport Police said: "We were called to reports of a fire underneath one of the carriages at Shrewsbury Railway Station.
"The station was closed. We were called shortly after 10.50am."
Replacement bus services were put on by Arriva Trains Wales.
Lynne Milligan, customer services director for Arriva Trains Wales said: “We can confirm that one of our trains experienced a technical problem resulting in smoke being emitted from the engine whilst it was in Shrewsbury station.
“The safety of our customers and staff is our primary concern and as such we worked with the fire service and evacuated the train and station as a precaution.
“There have been no reported injuries as a result of this incident.
“We will be working with our partners in Network Rail to restore services to normal as quickly as possible.”