Designing of railway rolling stock; designing of safety devices for railway signals; designing of railroad tracks (including road beds, track beds, railroad ties and rails); designing of machines, apparatus, instruments (including their parts) or systems composed of such machines, apparatus and instruments, all used for railroads; testing or research of railway rolling stock and their parts and fittings; testing or research of railroad tracks (including road beds, track beds, railroad ties and rails); testing or research of machines and instruments used for railroads