What is the purpose of rail bonding?

The purpose of rail bonding is to provide a continuous return circuit of low resistance. This is crucial for the safe and efficient operation of electric rail systems, where the electrical current needs a reliable path to return to the power source. Proper bonding ensures that there are minimal interruptions in the electrical flow, which helps maintain the performance of train systems, reduces the risk of electrical faults, and enhances the overall safety of the rail infrastructure.

Strong electrical connections between rail segments also help mitigate issues related to voltage drops and ensure that any stray currents are effectively managed. This contributes to the stable operation of signals and other electronic elements associated with train travel.

The other options, while related to various aspects of rail systems, do not directly address the core function of rail bonding. For instance, increasing train speed may depend on other engineering aspects such as track design and train technology. Supporting overhead cables is more relevant to the physical infrastructure than to the electrical integrity provided by bonding, and reducing friction on tracks pertains to track maintenance and design rather than electrical connections.