Abstract: Tip over of track crane is one of the most fatal accidents arising every year in the world. It is important to study an effective and available inspection method of tip over in order to avoid catastrophic accident happening. The traditional moment limiters of truck crane have some disadvantages because the designer reckons without the change of overturning moment caused by the change of corresponding working azimuth angle of track crane. After the torque being analyzed, the relation model Fmax = f(α, β, L), which is between maximum acceptable oil pressure of variable amplitude oil cylinder Fmax and arm-length of crane boom L, variable delta amplitude of crane boom β, working azimuth angle of turntable α is constructed, and the relation maximum acceptable lifting capacity model Gmax= g(α, β, L) is also set up. Based on the two theory models derived, the corresponding rollover protection methods are given respectively. In the end, the above models and methods are verified via site tests．The Gmax= g(α, β, L) model is taken as the application example, the simulation analysis and test results indicate that the theoretical value and the trial value of the maximum acceptable lifting capacity are consistent basically, and the coefficient of determination R2 between them is 0.93.

Key words: Maximum acceptable lifting capacity, Maximum acceptable oil pressure, Modeling, Rollover protection, Truck crane