Police are seeking suspects in Wednesday's fire that caused about $6,000 in damage.
The museum was closed at the time. Nobody was injured.
Wood says museum officials are checking security surveillance tape. DNA samples may be taken from inside the caboose.
The San Angelo Standard-Times reports the damage includes gutted custom-made seats, slashed window areas and broken equipment.
The depot complex includes two engines, a rail car and the caboose.
