Several spot fires that broke out along railroad tracks north of Highway 58 and Hart Flat Road Thursday merged into one and grew to about 100 acres, according to the Kern County Fire Department.
 
Capt. Tyler Townsend said "we believe a train" was the cause of the fires that were called in at 17:05.
 
They happened along a stretch between Hart Flat to the west and Keene to the east.
 
Aircraft, including four air tankers, responded, according to a Facebook post by Townsend.
 
Crews worked to keep the Hart Fire south of Caliente Creek and north of Highway 58, which remained open.
 
No evacuations were ordered.
 
No injuries were reported.
 
About 19:20 the fire was at 75 acres and 0 percent contained, but Townsend said it was "not really moving too much."
 
Then by about 21:15 it had grown to the estimated 100 acres and was 35 percent contained.
 
A total of 150 firefighters were assigned to the effort.
 
Fire hoses were stretched across the tracks to battle the flames, and firefighters asked the Union Pacific to stop all rail traffic over the Tehachapi Pass until tracks could be cleared of firefighters and equipment.
 
It was not immediately known how long train operations would be impacted.
 
On Facebook, people noted smoke could be seen and smelled in Tehachapi and as far away as Mojave.
 
Echoing many people, Andrea Dexter commented, "Thank you KCFD!!! I live in Keene, very close to the heli base. We were pretty scared!!!"
 
Christine Peterson.