Latest Scalextric sets are equipped with Sport Track and are ready to go, being complete with a mains power transformer and 12v DC dynamic hand held speed controllers. As speed is controlled by varying the voltage this is analogue control. Early Scalextric as well as most other 12v slot cars will run on Sport track while older sets equipped with Classic track can be extended by using a pair of converter tracks that allow connection with the later track. There are four basic Sport track sizes X1 - X4, X4 being the biggest. But any size is possible with the extensive range of add on track.
Great racing for the family is always guaranteed with Scalextric - its all down to skill on the controller. Remember all Scalextric sets are carriage paid to your home. Check out Micro Scalextric or Carrera Go if you don't have much space.