Barbed Wire
Tom Smith sees barbed wire separating him from the next part of land before him. The barbed wire is a symbol of the separation between the the new world of ingenuity and the old wild west.
Birds in Tree
We see birds flock instantly out of a tree when Howard's son begins to drive the car by himself. It is a symbol of the boy's imminent death.
Everything
Red's father gives him a bag of books when leaving him, and says that it holds everything. This is a symbol of his father giving him everything he and his wife can give him in the world in the midst of the Great Depression. And, that is an opportunity to have a life when there is no hope.
Fog
Tom sees Seabiscuit for the first time at 5 o'clock in the morning in the midst of deep fog. However, Tom sees right into his eyes, and this is a symbol that Tom sees beyond the fog, beyond the darkness into the soul of this horse.
Horseshoes
Tom can't find any of his horseshoes because Howard is giving them away to the press. This is a symbol that Howard is using Tom's tools for his horse training as publicity material to build hype for Seabiscuit. It shows the vast difference between the men.
