Design and Fabrication of A 100 Wp Solar-Powered Point Indicator Signal for Railway Depot Maintenance Areas

Conventional signalling in railway depots often relies on grid power, which contributes to resource depletion and operational costs. This study presents the design and fabrication of an autonomous, solar-powered point indicator signal to enhance safety and efficiency in nocturnal depot operations. The methodology encompassed electrical load calculation, mechanical design using AutoCAD, and prototype construction employing a 100 Wp monocrystalline panel, a 12V 200Ah battery, a charge controller, and LED arrays. Field testing at the Malang Locomotive Depot validated the system's performance. Results confirmed the prototype successfully illuminated 6-watt LED signals for 7 nightly hours. The battery depth of discharge (DoD) was maintained at 10.5%, promoting longevity. Peak solar irradiance of 851.3 W/m² ensured consistent energy harvesting. The total unit cost was estimated at IDR 8,156,500. This research demonstrates the technical and economic feasibility of a sustainable, off-grid signalling solution for railway maintenance areas, offering a replicable model for reducing carbon footprint and operational dependency.