This is perhaps the overriding theme of the story. The setting is Senegal in West Africa, a key part of France's colonial empire. The African railway workers are chronically underpaid and cruelly exploited by their French managers. But this isn't just because they're industrial workers; it's also because they're black Africans. Indeed, the two levels of exploitation are indissolubly linked at the beginning of the story. Later on, however, the workers' racial and national consciousness develops to the extent that the strike becomes a struggle not just for better pay and conditions but for Senegalese and African freedom from colonialism.

Solidarity comes in many forms in the story: racial, cultural, gendered, and human. The striking workers know that they will only be successful if they stick together in the face of overwhelming odds. But this is no easy task. Going on strike means no money, and no money means no food. There is no social safety net here; no welfare system. The strikers and their families are forced to rely on each other, digging deeper into their shared cultural heritage, which provides them with a source of enormous strength in their ongoing struggle.

At first, the women of the story are reluctant to support the strike. Life for African women is hard enough as it is, but without a regular pay packet to contribute to the upkeep of the home, it'll become almost intolerable. The women are not just victims of colonial exploitation; they're also subjected to the oppression of a traditional African society in which women are expected to be wives and mothers and to be subservient to men.

But the women start to see the bigger picture and support the strike with everything they've got. Like their husbands, they dig deep to find inner reserves of courage they never knew they had. Gradually, they start to take on a more prominent role in the struggle until eventually they become the driving force of the strike, holding a march on Dakar that will lead to victory. The message is clear. The anti-colonialist struggle can only succeed if women are truly accepted as equals.

The railway, though important to Senegal, represents colonial exploitation of the land. The country and its natural environment are valued not for themselves but as objects, things to be exploited for the wealth and power of the French colonialists. This stands in contrast to the traditional African way of looking at the natural world, a sacred world of beauty inhabited by spirits, a world to be preserved and valued for its own sake. But this is no mere nostalgia for a pre-industrial past. The railway is an important development, but it must be in harmony with its natural environment and serve the needs of the African people.