Train Battery Market Size, Share & Industry Analysis by Battery Type (Lead-acid, Nickel-Cadmium (Ni-Cd), and Lithium-ion), By Application (Starter, Auxiliary, and Propulsion), By Rolling Stock Type (Locomotive (ICE, Electric, Hybrid), Multiple Units (DMU, EMU, Hybrid), Passenger Coaches & Freight Wagons, and Metros /Light Rail/Trams), and Regional Forecast, 2026-2034