Editing Railway Labor Act (section)

==Representation elections==
The NMB has the responsibility for conducting elections when a union claims to represent a carrier's employees. The NMB defines the craft or class of employees eligible to vote, which almost always extends to all of the employees performing a particular job function throughout the company's operations, rather than just those at a particular site or in a particular region.

A union seeking to represent an unorganized group of employees must produce signed and dated authorization cards or other proof of support from at least 50% of the craft or class. A party attempting to oust an incumbent union must produce evidence of support from a majority of the craft or class and then the NMB must conduct an election.  If the employees are unrepresented and the employer agrees, the NMB may certify the union based on the authorization cards alone.

The NMB usually uses mail ballots to conduct elections, unlike the [[National Labor Relations Board]] (NLRB), which has historically preferred walk-in elections under the NLRA. The NMB can order a rerun election if it determines that either an employer or union has interfered with employees' free choice.