Automatic rail replacement control method

The invention discloses an automatic rail replacement control method. The bottom of a rail replacement cart is provided with a rail replacement mechanism for conducting collection and rerelease of rails, the rail replacement mechanism comprises two or more collection and release devices arranged in the operation direction of the rail replacement cart, and each collection and release device comprises a proportional valve and an oil cylinder connected with the proportional valve. An image detection device detects the displacement of the rails relative to railroad spikes in the operation walking process of the rail replacement cart; a displacement sensor detects the motion stroke of the oil cylinders of the collection and release devices; a control system acquires the displacement of the rails relative to the railroad spikes and controls the power and signal input of the proportional valves according to a detection value of the displacement sensor, so that motion control over the oil cylinders is achieved; the c