The great red horse
Center / center-left, the massive animal lunging forward and to the left, filling the heart of the canvas
The picture’s engine: a huge red-brown draft horse, far larger than any worker, caught mid-surge. It is not a true horse-color so much as a charge of energy, and everything in the composition is dragged into its motion. The literal fact on the canvas is the lunging red horse; the reading of it as the city’s own growth, a power the men can barely hold, is a reading, and a fair one.