This amendment to § 192.65(a) and Appendix A to Part 192 (1) incorporates by reference the 1972 edition of the American Petroleum Institute document API RPF51, entitled "API Recommended Practice for Railroad Transportation of Line Pipe." and (2) requires that in the case of certain pipe transported by railroad, the transportation be In accordance with the 1972 edition of APIRP5I except that before February 25. 1975, the transportation may be in accordance with the 1967 edition. The 1967 edition of API RP5L1 is currently incorporated by reference in Part 192. Incorporation by reference of the 1967 edition is continued so as not to preclude the use of pipe transported in. accordance with that edition before the effective date of this amendment.