Classic conventional pivoting tonearm moves freely, it is "pulled" by the stylus across the record. Because of the move that it makes conventional tonearms have tracking distortions. Record players with linear/tangential tonearms have zero tracking distortion. The tonearm positions the cartridge at the same 90 degree angle at which the record were cut. In the past meany great constructions of record players with linear tonearm were complicated and heavy. In order for the linear tonearm to move, it was/is necessary that the arm is controlled by electric motors. This motors are pushing the arm across the record but the mechanical complexity of this models gives more points for failure. All models with linear tracking tonearm in Pre-audio constructions have low mass and simple construction. That allowed like in conventional pivoting tonearms that the tonearm is "pulled" by the stylus across the record. How efficient that solution is you can see on videos.