§ 2. Classification of transportation corporations. A transportation corporation shall be either,
1. A gas corporation, an electric corporation or a gas and electric corporation.
2. A telegraph corporation, a telephone corporation or a telegraph and telephone corporation.
3. A water-works corporation.
5. A ferry corporation.
6. A pipe line corporation.
7. A freight terminal corporation.
8. A district steam corporation.
9. Sewage-works corporation.