The invention discloses a dual-source power supply 
system and a dual-source 
power engineering vehicle. The dual-source power supply 
system comprises a main circuit for power supply of an overhead 
contact system, a main circuit for power supply of a traction battery, a rectifying module, an 
inverter module and an auxiliary 
inverter module, a power supply switching device for receiving a power supply command of the overhead 
contact system or a power supply command of the battery, and a controller; The dual-source power supply 
system will not emit polluting gas, so as to meet the low-emission 
environmental protection requirements of 
urban rail. Moreover, the dual-source power supply system can be applied to the two power supply 
modes of the 
catenary and the traction battery, and the automaticswitching of the two power supply 
modes can be realized by using the switching instruction of the power supply switching device and the controller. Therefore, when there is a power area, the application can select the power supply mode of the 
catenary (power supply mode satisfying the power supply mode of the national railway and AC-DC-
AC power supply system), which saves power and has higher efficiency; As that power-
free zone is entered, the application can be switch to the traction battery power supply mode, and the electric 
engineering vehicle can still work normally and has high reliability.