Brennan Gyro-Monorail. Early 1900s.
https://diqn32j8nouaz.cloudfront.net..._monorail1.jpg
https://diqn32j8nouaz.cloudfront.net..._monorail2.jpg
https://diqn32j8nouaz.cloudfront.net..._monorail3.jpg
More:
https://en.wikipedia.org/wiki/Gyro_monorail
http://www.douglas-self.com/MUSEUM/L...an/brennan.htm
Previously:
https://www.homemadetools.net/forum/...184#post141648
