A solenoid-driven automatic bus transfer switch may automatically transfer one or more electrical loads from a first power source to a second power source, or vice versa, in the event of a power failure or other casualty that affects either power source. The transfer switch may be operated in response to the energization of a solenoid coil, which causes a main shaft having a transfer element to rotate from being in contact with the first power source to being in contact with the second power source. The transfer element may be spring-mounted to the shaft, which ensures that a sufficient electrical contact exists between the surfaces of the transfer element and the respective leads of the first and second power sources, regardless of any wear or degradation that may be experienced at any of the surfaces.