sentences:  In 2009, the offered product line expanded again.The new Paragon2 line utilizes an integrated DCC decoder that can be operated on DC track as well, as well as DCC sound capability and steam generating units on many locomotives.In 2015 the company introduced Rolling Thunder, US patent #7,634,411, a system that transmits the low frequency bass sounds from a locomotive to a subwoofer located beneath the model train layout.