Priority directions and events among basic industries of municipal electric transport is resource saving in a transport system of underground passage during his exploitation. First of all this problem must be decided by scientific accompaniment, id est on the stage of planning of details and knots of transport vehicles. One of the basic tasks decided on the stage of planning is an increase of bearing strength of details due to the analysis of their tensely-deformed state. The article is sanctified to the calculation of supply of carrying capacity of stringer of front carriage of subway at operating under the middle of the equipartition loading case-insensitive transversal forces. Priority of research theme is reasonable, an aim and tasks are set forth. Two going offer near the power calculation of bearing strength of stringer: calculation on the assumed tensions and on the maximum states. The resilient models of beams are examined in both cases. In case of calculation on the maximum state mechanics of origin of plastic hinges is first of all grounded in the places of the hard fixing of ends of beam. A beam saves the bearing strength still. At the further height of the external loading appearance of plastic hinge is justified even in the middle of beam with a simultaneous loss by the beam of bearing strength. For the design of behavior of beam in accordance with her descriptions, including on tensions and by the condition of loss of her bearing strength. The mathematical raising of task of calculation of bearing strength of stringer at the calculation of possible tensions and maximum state is examined case-insensitive transversal force. Bearing strength of stringer is analysed at a calculation on possible tensions and on the maximum state. The analysis of the got results allows to judge about efficiency of an offer mathematical model on the whole. Got equalizations for the maximally possible loading at a calculation on the maximum states and on possible tensions allows reliably to estimate bearing strength of stringer in both cases. The increase of bearing strength of beam at a calculation on the maximum state is thrice-repeated. Drawn conclusion about adequacy of analysis of bearing strength of stringer.
