Quoting from INTRODUCTION TO MODULE STANDARDS & RECOMMENDED PRACTICES - NMRA Bulletin March 1990 -
These standards and RPs have been assembled from data sent in from module groups that are actively building and operating these units in all parts of the country..... ~
NMRA SIGs
Within the NMRA there are many Special Interest Groups (SIG). Among them are modular groups for each scale and they have much to offer the builder in the way of data and information. These groups are listed from time to time in the BULLETIN. It is suggested that the newcomer to module building study the Standards, RPs, and Data Sheets of both NMRA and the SIG. Before starting it would be useful to attend a meet where modules are set up and operating and discuss the pros and cons of both module types and then decide which type best suits your goals. Good preparation will reduce the number of problems when interfacing your module with others for the first time. There are often small adjustments to be made out if care is taken and proper planning is done, these can be kept to a minor nature.
We are most grateful to NTRAK for the courtesy of using some of their drawings which have evolved from more than 15 years of successful construction and operation. The basic methods of construction are applicable to the other scales. Only the cimensions need be changed. In the case of 0 scale, 1" x 6" side panels are suggested due to the increased weight of the models which will be used in the operation. Data Sheets will show how other groups differed in some of the construction details so it is advisable to study all available material, choosing chose most suitable to your own particular needs or desires. Scales larger than 0 should use suitable larger side panels according to the weight they are expected to carry. The engineering committee is always ready to help those in need, with suggestions as to the way to approach a problem area.
Electrical Standards may differ with each scale. Check the SIG, of your scale.