49 CFR §244.7

1. (a)A person subject to a requirement of this part may petition the Administrator for a waiver of compliance with any requirement of this part. The filing of such a petition does not affect that person's responsibility for compliance with that requirement pending action on such a petition.
2. (b)Each petition for a waiver under this section must be filed in the manner and contain the information required by part 211 of this chapter.
3. (c)If the Administrator finds that a waiver of compliance is in the public interest and is consistent with railroad safety, the Administrator may grant the waiver subject to any conditions the Administrator deems necessary.
4. (d)The procedures governing a petition for a waiver that are prescribed under this part apply only to FRA's disposition of such a petition. A person seeking a waiver of a Surface Transportation Board regulation would need to file a petition for a waiver with the Board. (See 49 CFR 1106.5.)