 First Great Western planned to supplement (but not replace) its InterCity 125s with 14 Class 180 "Adelante" trains, which can travel at the same speed.Because every carriage has an underfloor engine, they can accelerate approximately twice as quickly, which reduces journey times and allows for more frequent services.However, in-car noise levels are higher than in the InterCity 125 because of the underfloor engines, which, combined with less-comfortable seats and harsh interior lighting, has made them unpopular with passengers.