49 CFR § 9.17
Legal proceedings between private litigants: Procedures for taking testimony
November 18, 2020
(a) Testimony of an employee of the Department may be taken only at the office to which the employee is assigned, or any other place designated by agency counsel. Additional conditions may be specified under §9.15(c) of this part. The time shall be reasonably fixed to avoid substantial interference with the performance of the employee's or agency counsel's official duties.
(b) Upon completion of the testimony of an employee of the Department, a copy of the transcript of the testimony shall be furnished, at the expense of the party requesting the testimony, to agency counsel for the Department's files.