The PTC Model III is designed for users wanting to solve the problem of reliable turntable indexing. Situations where the PTC Model III 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 III (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.

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

To fit your system to your tastes and requirements, four Track Selector Modules are available; the standard PTC Model III is supplied with either the Rotary or Pushbutton Track Selector:

  • Rotary (Standard): indexes 12 tracks
  • Pushbutton (Standard): indexes 12 tracks
  • Chubb/Universal (Upgrade Option): indexes up to 24 tracks, suitable for interface to Chubb/Computer control
  • Keypad (Upgrade Option): indexes up to 99 tracks



  • Fully user programmable indexing for up to 12 tracks (standard Rotary or Pushbutton selector)
  • Indexes both bridge ends
  • Expandable up to 24, 48, or 99 tracks
  • Track selection using rotary switch, pushbuttons, keypad, or via external computer (e.g., Chubb)
  • Very fine 0.025 indexing resolution
  • Simple index programming
  • Select from 14,400 possible stopping locations
  • High torque stepper motor with internal gearing
  • Heavy duty motor for "O" and "G" applications
  • Quiet, smooth, slow operation
  • Programmable maximum speed: 0.15 to 0.50 RPM
  • Programmable momentum
  • Bridge track power polarity control ("automatic track power reversing")
  • Optional track power routing with the new APR Model I

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

For full details about the PTC Model III 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.