What political events led to the Separate Car Act that was upheld in Plessy v. Ferguson?

Question

One often reads that in 1896 in the case of Plessy versus Ferguson, the United States Supreme Court let stand a Louisiana law, the Separate Car Act, that required white and non-white passengers to ride in separate cars on trains. But what is the story of the political events leading to the passage of that law in 1892 (if 1892 is right)?

Some wild guesses:

• Passenger trains were starting to become big business but earlier they'd played a more minor role in the transportation industry in Louisiana, and so escaped the attention of the legislature. When large numbers of people started using them, some regulation started happening. As I said, a wild guess; I have no idea whether this is true.
• Could it have been a reaction by segregationists against some partial desegregation by some railroads? I can imagine some economic incentives to partial desegregation. Say the tickets on the white car are sold out and some passengers who want to get where they're going don't mind riding in "colored" car if that will accomplish their purpose. Again, a wild guess.

Answer 1

It was 1890, not 1892, when Louisiana passed the Separate Car Act.

The political events that led to these Jim Crow laws were white supremacy that the Civil War and Reconstruction failed to eliminate (they didn't make a dent), the end of Reconstruction, and numerous decisions by the Waite Supreme Court. The end of Reconstruction resulted in Federal troops being withdrawn from the south. Those Federal troops protected the voting rights of the freed slaves. Without their presence, the freedmen found it harder and harder to vote. The Waite Supreme Court issued several decisions that narrowed the scope of the Civil War Amendments and made it easier for the south to disenfranchise the freed slaves.

The Republican-led southern state legislatures were replaced with Democrats soon after Reconstruction ended in 1877. Southern states started passing Jim Crow laws shortly thereafter. By the 1890s, those laws kept white and non-white separate on trains and trolleys, in restaurants and theaters, in restrooms and around drinking fountains, but most importantly, out of polling booths. All kinds of places where people might come together were subject to the numerous Jim Crow laws.

Passenger trains were starting to become big business but earlier they'd played a more minor role in the transportation industry in Louisiana, and so escaped the attention of the legislature.

This is exactly backwards. Passenger trains were very big business in the 1880s and 1890s. The Separate Car Act was one of the very first post-Reconstruction Jim Crow laws passed in Louisiana. It preceded banning of interracial marriage by four years, mandating separate public schools by seven years, mandating separate bars (drinking establishments) by eighteen years.