Railway Multiple Units Market Size, Share & Industry Analysis by Propulsion (DMUs, EMUs, and Hybrid), By Train Set (Up to 2 Cars, 3-6 Cars, and 7 Cars & Above), By Application (Rapid Transit/Metro, Suburban & Commuter Rail, and Intercity Rail), By Component (Propulsion & Power, Carbody & Structures, Bogies & Running Gear, Electrical & Control, Passenger Interior, Braking Systems, Doors & Access, Couplers & Gangways, and Auxiliaries), and Regional Forecast, 2026-2034