subpart G, part 213 of title 49, Code of Federal Regulations, by requiring that a qualifying Track Geometry Measurement System (in this section referred to as TGMS ) operate over the following track classifications at the following frequencies: (1) For operations at a qualified cant deficiency, Eu, of more than 5 inches on track Classes 1 through 5, at least 4 times per calendar year with not less than 43 days between TGMS inspections. (2) For track Class 1, operating more than 15 million gross tons (MGT) on an annual basis, at least once per calendar year with not less than 170 days between TGMS inspections. (3) For track Class 2— (A) less than 15 MGT annually, at least once per calendar year with not less than 170 days between TGMS inspections