Automatic Train Operation System Market Size, Share & Industry Analysis, By Grade of Automation (GoA 1, GoA 2, GoA 3, and GoA 4), By Deployment Type (Greenfield Deployment and Brownfield Modernization/Retrofit), By Signaling (CBTC-Based ATO, ETCS-Based ATO, Conventional/Legacy Signaling-Integrated ATO, and Other Proprietary Train Control-Integrated ATO), By Application (Metro & Subway, Light Rail & Tram, Commuter & Suburban Rail, Mainline & High-Speed Rail, Freight Rail, and Automated People Movers), By Component (Hardware, Software, and Services), and Regional Forecast, 2026-2034