Which of the following is NOT considered a safety system on the TLB?

The correct answer is engine size, as it does not serve as a safety feature on a Tractor-Loader-Backhoe (TLB). Safety systems are designed to protect the operator and others in the vicinity during operation.

The loader arm service lock is crucial for safety because it prevents the loader arms from moving unintentionally, thereby safeguarding the operator and bystanders when performing maintenance or inspections. The reverse warning alarm is another important safety measure, as it alerts nearby personnel of the machine's movement, reducing the likelihood of accidents when the operator is reversing. Similarly, the seat belt is a fundamental safety system that secures the operator in case of sudden movements or accidents, while the horn serves as an audible signal to warn others of the machine's presence or actions.

In contrast, engine size pertains to the machine's power and performance capabilities, which, while relevant for operational considerations, does not influence the safety measures directly. Understanding the distinct roles of safety systems helps in maintaining a safe working environment when operating TLBs.