Your definition of generation is 3-5 times longer than the usual definitions.
Addressing approximate timeframe of commercialization:
> the train
1812. http://en.wikipedia.org/wiki/Salamanca_(locomotive)
> the telegraph
1837, +25 years. http://en.wikipedia.org/wiki/Cooke_and_Wheatstone_telegraph
> the telephone
Bell/Gray was 1876, commercialization by 1878. +40 years. http://en.wikipedia.org/wiki/History_of_the_telephone
> the radio
Mid-to-late 1890s. 1895-1877=18 years. http://en.wikipedia.org/wiki/Invention_of_radio