If you look in the config.txt file of the ATSF C30-7 you'll see that there are 2 smoke containers attached to the a.exhaust attachment point. The first one is:
smoke0
{
texture <kuid2:45324:10116:1>
attachment "a.exhaust0"
mode "time"
color 255,128,43,220
accel 0.5,0.3,0
rate 15
velocity 2
lifetime 0.5
minsize 0.4
maxsize 1
enabled 0
}
The texture kuid is the flame. You might try copying this smoke container to another loco to see if it works.
Bob Weber