We taxied onto the departure runway at EWR one morning when everything was covered in ice due to an overnight freezing rain. You could taxi a L 188 with prop pitch control even without any effective nose wheel steering or braking effectiveness. As we sat in the center of the runway, the FE shifted the engines up to the flight RPM. Even at flat pitch, the airplane started to slowly slide sideways off to the left side of the runway. the Captain advanced the power levers a tad and the aircraft regained rolling traction and moved slowly directly forward. He said, "Tell them were cancelling and going back to the gate. We don't get paid to do this". I had never realized most runways are designed 1 1/2 feet higher in the middle.