Final answer:
Workers at an auto manufacturing plant who picket a railroad company delivering parts to their factory are engaged in a secondary picket, aiming to disrupt the supply chain and gain leverage in negotiations for better benefits and wages.
Step-by-step explanation:
The workers at an auto manufacturing plant who are on strike and picket the railroad company that delivers parts to the factory are engaging in what is known as a secondary picket. This is when employees picket a company that is not their direct employer to leverage pressure against the primary target of a labor dispute. In contrast, a primary picket involves workers picketing their own place of employment. A wildcat picket is an unofficial strike action without union approval, and a sympathy picket occurs when workers strike in solidarity with other workers who are striking at a different workplace. Considering the information given, these workers are participating in a secondary picket to disrupt the supply chain and gain leverage in their struggle for good benefits and higher wages.