The accident took place last evening when the feline was run over by Veraval - Delvada passenger train at Jamvala village of Una taluka in the district, he said.
"On seeing the lioness on the track, the loco pilot applied brakes, but could not save her as she was near the loop of the railway track," K Ramesh, deputy conservator of forests, western Gir Lion National Sanctuary area, told PTI.
The forest team patrolling in the area was rushed to the spot, he said, adding that they have recorded the statement of the loco pilot, co-loco pilot and the guard of the train in connection
with the accident.
Officials added there were two lionesses roaming on the railway track. While one of them managed to jump away, the other got trapped near a loop on the track, he said.
During interrogation, the loco pilot of the train said he could not see the lioness due to thick vegetation on one side of the railway track, Mr Ramesh said.
The accident site is a revenue area located about one kilometre away from the Gir National Park and Wildlife Sanctuary, which houses 411 Asiatic lions, as per a 2010 census, he said.
"We will be talking to concerned railway authorities to discuss ways to reduce the speed limit of trains on this stretch," he added.
Earlier this year, in January, a speeding goods train had run over two lionesses near the sanctuary.