The Computer/Model Railroad Interface

The Computer/Model Railroad Interface (C/MRI) is a computer data acquisition system that can be used to control the operation of model railroads. It is not DCC, but can be used in conjunction with DCC.

Put most simply, the C/MRI reads input devices (switch positions, push-button status, block occupation status, throttle direction), makes decisions about the layout based on a user-defined set of parameters (generates signal aspects, block/cab assignments), then sends output commands to devices on the railroad (signal LEDs, turnout machines, block power assignments).

On the MKT, St. Louis Sub, the C/MRI is used to provide block assignments, read block occupancy, drive trackside signals, and display the dispatching console.  Unattended operation is also possible, but not used during operating sessions. 

The C/MRI was designed by Bruce Chubb, and was presented in a 16-part series of articles in Model Railroader in the mid-80s. The system has proven very popular for both model railroad and non-model railroad applications.

For a complete explanation of the C/MRI, see the February 1985 through August 1986 issues of Model Railroader, or consult Bruce Chubb's book, Build Your Own Universal Computer Interface (Second Edition, ISBN 0-07-922639, 1997).   The JLC Enterprises web site describes the many applications of the C/MRI and provides information on building a C/MRI system.