Five years later, in 1964, the same utility installed the first pre-engineered combined cycle power plant at its San Angelo, TX, power station. The Westinghouse gas turbine used for that application was a supercharged model W301, nominally rated at 25 MW. The rating on the steam turbine was 85 MW, for an overall combined cycle plant output of about 110 MW, and the thermal efficiency achieved was more than 39%, the record for gas-fired power plants in the US for quite some time.