Jim:
As Phoebe noted the UT4 comes with a coiled cable. It will comfortably reach about 5 feet. It is not detachable from the throttle. Tony's Trains (http://www.tonystrains.com) sells six wire cables and couplers that could be used to lengthen the cord or you could add additional UP5 panels around the layout to extend your reach.
Joe
It comes with a decent length coiled cord.
Dave
Lackawanna Route of the Phoebe Snow