Looking at the link that Louis provided, it says it has Proto Sound 3 installed. This is MTH's proprietry digital control system, known as D.C.S. It is incompatible with any other control system i.e. you must use their Power supply and control cab to operate your train/s, and only their brand of locomotives will run on it. Basically you will be "locked in" to that brand's choices of engines. I'm not an "O" gauge guy but if Louis says their can be problems re compatibility in that gauge, then care will be needed when selecting anything from a maker that requires the use of track power.
MTH tried to break into the HO market with his DCS system, but fell foul of the entrenched DCC (Digital Command Control), which is the most prevalent in that scale (N scale as well). Allied to his refusal to make the decoders available to other brands of locos for factory fitting as well as aftermarket fitting by users, he has now been forced to provide DCC capability in his products, but O maybe not.