Interesting to me as we here (in Hastings, UK) have a 1928 open top trolleybus (Happy Harold) which was fitted with a diesel engine when the wires were taken down in 1959 - it still runs and I get to drive it sometimes. I presume that yours, like ours, has had it's electric running gear removed and can no longer run as an electric vehicle? Does the orange, grey and white livery represent any company or transit operator colours?
oldelephantstew the livery is Metro Transit Operating Company. This is what it would have been painted as new in 1976. The old controller was from a 1947 bus and was an electro-mechanical system built by General Electric. Add an air throttle in the 70’s and you have a jerky start every time. All that was removed and a Detroit Diesel 6V71 was installed with a Spicer 183 transmission. Two of our other older 1957 buses have an AEC AH-690 engines. Look for them on my other videos. One shows all our equipment.