Okla. Admin. Code § 730:40-5-2
The following words and terms used in this Chapter shall have the following meaning, unless the context clearly indicates otherwise:
"Class II and Class III railroad" means a railroad that is classified by the United States Surface Transportation Board as a Class II or Class III railroad;
"Eligible taxpayer" means any Class II or Class III railroad; and
"Qualified railroad reconstruction or replacement expenditures" mean expenditures for:
Added at 23 Ok Reg 429, eff 11-16-05 (emergency)
Added at 23 Ok Reg 2879, eff 6-25-06