How can stuck brakes be released on an M-7 car?

Using the service brake cutouts (SBCO) to release stuck brakes on an M-7 car is the correct approach. The SBCO allows the operator to isolate and deactivate the air brakes on individual cars, which can be crucial when faced with an issue like stuck brakes.

In practice, if the brakes are stuck due to a malfunction or external factor, utilizing the service brake cutouts helps in effectively managing the situation without compromising the safety mechanisms of the train. It offers a controlled way to handle brake issues, allowing you to proceed with minimal risk and facilitating movement in scenarios where immediate repairs may not be possible.

The other methods mentioned may not be appropriate for releasing stuck brakes. Emergency brakes are intended for situations requiring immediate stopping power, not for addressing stuck brakes. EP cutouts focus on the emergency braking system but do not directly address service brake issues. Lastly, using wheel chocks is a safety measure intended to prevent movement of the train rather than resolve brake malfunctions, so they would not assist in releasing stuck brakes.