Final answer:
The train operator should immediately stop the train and inspect the grounded shoe beam for damage, ensuring passenger safety and informing the maintenance team.
Step-by-step explanation:
The train operator should take immediate action upon noticing severe arcing fumes from the shoe beam beneath their cab. The best course of action for the safety of the passengers and the integrity of the train system would be to stop the train as soon and as safely as possible and inspect the shoe beam for any damage.
This is because a grounded shoe beam can be indicative of a significant electrical fault that may pose a direct risk to the operation of the train and the safety of everyone on board. Continuing to operate the train could lead to further damage and increased hazard, while calling for emergency assistance without assessing the situation may not be necessary if the issue can be resolved through standard procedures.
The operator should also report the issue to the maintenance team, ensuring they are informed and ready to take the necessary steps to repair the damage and prevent future occurrences.