Train services were disrupted while emergency services dealt with the incident in Perth.
Firefighters were called to the scene at the Pets at Home store at St Catherines Retail Park at around 2.13am on Saturday.
The Pets at Home store, a B&M store and a vacant unit have all been damaged in the blaze.
Animals from the pet store were not injured and have been moved to a safe site.
The Scottish Fire and Rescue Service sent 10 fire engines and other specialist appliances to the scene.
ScotRail tweeted that there was some disruption to services for a time as some lines were closed due to the fire.
However at around 8am they were informed that it was safe to reopen the line and said that services were returning to normal.
There were no reports of any injuries.