In present work peculiarities of electron transport with transition from quantum wires with smaller cross sections to quantum wires with larger cross sections are studied. Electron transition probabilities through corresponding contact regions of such quantum wires are calculated as functions of charge carrier kinetic energy and quantum wire cross sections ratio. Peculiarities of electron pass through the defects in quantum wires in the form of rectangular grooves and steps are also studied. Electron transition probabilities through the defect regions are calculated as functions of electron kinetic energy and geometry and size of the defects. Probability density distributions of electron detection in different regions of simulated structures have been calculated.