On John Cutler said
Which brings me to another point. Why do we publish P4 standards? Why do the Stores stock P4-specific items? This sends the wrong message; we are not sure what we are about.
From “About the Society”, on the front page of the EMGS website?
“The letters EM reflect the original 18mm gauge standard although this was further refined to 18.2mm. In addition we also support modellers working to the more demanding Protofour (P4) standards, with a track gauge of 18.83mm.”