Engines that can run in either directions.

[jeffmorris]

I know that steam engines that can run in either directions. I thought that gas and diesel engines can't run in either directions until I found out that a passenger railcar built in 1910s had a gas engine that can run in either directions by moving the camshaft. From searching the Internet, I found out that some two-stroke engines can run in either directions but not 4-stroke engines. Marine two-stroke engines can run in either directions. The railcar must have a two-stroke engine. Search the Internet for McKeen Motor Car Company.

[ducked]

Diesels can run backwards by accident sometimes, setting fire to the intake air filter with the reversed hot exhaust gases. I'd guess this may be restricted to 2-stroke diesels like the Detroit.

I first encountered this "fun fact" in the Taiwan DMV ""Mechanical Knowledgee"" test which I took by accident, thinking I needed it for a Taiwan car drivers license.

Its apparently only required for truck drivers.

Would have been tough to pass since I have some mechanical knowledge and understanding, a severe handicap for any Taiwan test. About a third of Q+A were utter BS, but this is merely obscure.

The Messerschmit and Bond 3-wheelers had reversible engines instead of a reverse gear, giving them top gear in reverse, which must have been scary.

[Blue Bowtie]

And then there is this system:

https://www.youtube.com/watch?v=_zR19_XDBgc