What must always be checked regarding brake systems before train operation?

Ensuring that the brakes on the cars are cut-in is crucial before train operation because this confirms that the braking system is fully operational and ready to respond in the event of an emergency. When the brakes are cut-in, it indicates that they are engaged and will function correctly to slow down or stop the train as needed during normal service and emergencies.

Proper brake functionality is key to safety in train operations. If the brakes are not cut-in, there is a risk of having an ineffective braking system, which can pose a danger to the crew, passengers, and overall operational integrity. The practice of verifying that the brakes are cut-in is a standard safety protocol in train operation that contributes significantly to preventing accidents and ensuring reliability on the tracks.