1. (a) The guard check and guard face gages in frogs shall be within the following limits—

   Table 1 to § 213.143(a)

   Class of track	Guard check gage	Guard face gage
   The distance between the gage line of a frog to the guard line 1 of its guard rail or guarding face, measured across the track at right angles to the gage line,2 may not be less than—	The distance between guard lines,1 measured across the track at right angles to the gage line,2 may not be more than—
   Class 1 track	4′61⁄8″	4′51⁄4″
   Class 2 track	4′61⁄4″	4′51⁄8″
   Class 3 and 4 track	4′63⁄8″	4′51⁄8″
   Class 5 track	3 4′61⁄2″	4′5″
   1 A line along that side of the flangeway which is nearer to the center of the track and at the same elevation as the gage line.
   2 A line five-eighths of an inch below the top of the center line of the head of the running rail, or corresponding location of the tread portion of the track structure.
   3 See paragraph (b) of this section.

2. (b) For any heavy-point frog (HPF) on Class 5 track, the guard check gage may be less than 4′6 1/2″ but not be less than 4′6 3/8″, provided that:

   1. (1) Each HPF and guard rails on both rails through the turnout are equipped with at least three serviceable through-gage plates with elastic rail fasteners and guard rail braces that permit adjustment of the guard check gage without removing spikes or other fasteners from the crossties; and
   2. (2) Each HPF bears an identifying mark applied by either the track owner, railroad, or the frog manufacturer that identifies the frog as an HPF.

[85 FR 63388, Oct. 7, 2020]