What you should you not do when coupling two carriages?

Explanation

Correct answer: Loosen the shoe brakes of the carriage to be coupled.

During the trailer coupling manoeuvre, it is crucial that the trailer to be attached is completely immobilised. Releasing its brakes could cause the vehicle to move uncontrollably, which poses a direct hazard to the person carrying out this procedure and prevents a safe and correct coupling. The brakes may be released only after the entire process has been successfully completed.