Electrification is fairly easy once you have generators, motors, and even modest transmission infrastructure. Many early generator plants were for quite limited service areas, or even single applications such as a factory or electrified rail system. Some of those later expanded to sell surplus or additional power, Duke Energy (now the Southern Company) being once such instance, I've recently learned.
The basics of electrical traction design were optimised to a large extend fairly quickly, especially relative to ICE technologies, which are relatively more complicated, and high-power (as well as high-reliability) ICE propulsion took considerably longer to develop. So, 1860s--1920s or so for electrical vs. 1890s--2000s for ICEs, which saw improvements in basic design, metallurgy, machining, emissions controls, injection, and computer controls, among others.
The alternative was steam locomotion, which was still being used in the West into the 1950s, when diesel-electric traction largely replaced it. China didn't retire its last commercially-operating steam locomotives until the 2010s, and possibly later. (There's a set of photographs of a train engineer who'd graduated from steam to high-speed rail over his career, and possibly within only a decade or so.)
In the past decade or so we've seen increasing limits on ICEs, most especially of their fundamental characteristic of carbon emissions, whilst EVs are benefiting from incremental advances in battery and other technologies reaching past a critical tipping point.
The basics of electrical traction design were optimised to a large extend fairly quickly, especially relative to ICE technologies, which are relatively more complicated, and high-power (as well as high-reliability) ICE propulsion took considerably longer to develop. So, 1860s--1920s or so for electrical vs. 1890s--2000s for ICEs, which saw improvements in basic design, metallurgy, machining, emissions controls, injection, and computer controls, among others.
The alternative was steam locomotion, which was still being used in the West into the 1950s, when diesel-electric traction largely replaced it. China didn't retire its last commercially-operating steam locomotives until the 2010s, and possibly later. (There's a set of photographs of a train engineer who'd graduated from steam to high-speed rail over his career, and possibly within only a decade or so.)
In the past decade or so we've seen increasing limits on ICEs, most especially of their fundamental characteristic of carbon emissions, whilst EVs are benefiting from incremental advances in battery and other technologies reaching past a critical tipping point.