What is the primary purpose of the lower carriage in an escalator?

The primary purpose of the lower carriage in an escalator is to provide proper tension on the step chain axles. This tension is crucial for the smooth operation of the escalator, as it ensures that the moving steps remain aligned and operate efficiently without slipping or jamming. The lower carriage plays a key role in maintaining consistent contact between the step chains and the escalator's drive system, thereby affecting the overall performance and reliability of the escalator.

While other components and systems contribute to the escalator’s operation—such as the handrails for user safety, speed controls for operational performance, and guiding elements for stability—the lower carriage specifically focuses on the tensioning needed for the step chain, which is vital for the proper functioning of the escalator. Without adequate tension, issues could arise that hamper the escalator’s ability to transport passengers safely and effectively.