Hall-Scott was known in later years for having built many excellent truck and bus engines, all gassers, but they started out building aircraft engines and self-propelled railroad passenger cars.
This is a very early engine, out of a self-propelled railroad passenger car (predecessor of the Budd RDC). A famous Hall-Scott application was the 1090 CID 240 HP engine in the M26 Dragon Wagon.
Hall-Scott’s demise was the result of the inability to develop a diesel engine after Hall and Scott were both gone.