The 4.20 version of JMRI for Mac is available as a free download on our website. The following version: 2.1 is the most frequently downloaded one by the program users. This Mac download was scanned by our built-in antivirus and was rated as malware free. JMRI.2.12.dmg is the most frequent filename for this program's installer. The software lies within Design & Photo Tools, more precisely 3D Modeling. This free Mac application is an intellectual property of jmri.
From the developer:
This applications is made by some tools for model railroad computer control. It is written in java and it is independent of specific hardware systems. It is intended as a jumping-off point for hobbyists who want to control their layouts from a computer without having to create an entire system from nothing.
You may want to check out more software for Mac, such as DecoderPro, which might be related to JMRI.