Bar your link takes me to this document (emphasis added)

GUIDE FOR HEARING OFFICERS IN NLRB REPRESENTATION AND
SECTION 10(K) PROCEEDINGS

Correct me if I'm wrong, but we operate under the RLA as administered by the NMB.


With regards to NLRB jurisdiction, I found the following on Wikipedia:

The Board's jurisdiction is limited to private employees and the United States Postal Service; other than Postal Service employees, it has no authority over labor relations disputes involving governmental, railroad and airline employees covered by the Adamson Railway Labor Act, or agricultural employees.