The PTC Model 4 is designed for users wanting to solve the problem of reliable turntable indexing. Situations where the PTC Model 4 will be of benefit include:

  • Turntables with many lead and service tracks
  • Turntables where the tracks are hard to see, particularly those in corners or near the rear of the layout, or those with dim lighting;
  • Layouts with high quality, highly detailed rolling stock and bridge modeling where "hands off" indexing is preferred;
  • Any situation where reliable, accurate indexing will enhance layout operation and enjoyment.



The PTC Model 4 (Programmable Turntable Controller) is a user programmable turntable indexing system for use in new or existing N, HO, S, O, and some G scale turntables. The turntable's indexing positions are programmed into the PTC by the user, who "teaches" the PTC where the lead and service track positions are. The PTC does not use infrared diodes, tab stops, or any mechanical methods for indexing. Once programmed, the PTC remembers the user's track locations-- even when the system power is turned off. During operation, the user selects the desired lead or service track from the control panel. The PTC then automatically determines the shortest direction of travel, simulates turntable momentum by ramping up the bridge to a user-determined maximum speed, then ramps it down as it approaches the desired service or lead track location. The PTC then stops the bridge at the exact location desired, within 0.025 degrees.

The basic PTC is comprised of : the Controller and Track Selector Module, Stepper Motor, Motor Mount Kit (optional), and Power Supply.


  • Fully user programmable indexing for up to 99 tracks
  • Indexes both bridge ends
  • Very fine 0.025 degree indexing resolution
  • Simple index programming
  • Select from 14,400 possible stopping locations
  • High torque stepper motor with internal gearing
  • Quiet, smooth, slow operation
  • Programmable maximum speed: 0.15 to 0.50 RPM
  • Programmable momentum
  • Bridge track power polarity control ("automatic track power reversing")

A high quality clear anodized steel coupler is included with your system.

For full details about the PTC Model 4 and the options available, download a copy of the Product Overview. Please visit the Downloads page of this site where all the user manuals, application notes, and other documents are available for download.