snake and crane wing chun

[Hendrik]

So hendrik what is your definition of the word "Engine"

why do you feel Wing Chun can only be a snake engine but not both?

Also with that in mind...What engine is the Tiger and Crane?

Engine means characteristics the practioner's body transform into.
Example.
A vampire cannot be a werewolf. A werewolf is not a fairy. A werewolf fight different compare to a vampire. One cannot be a werewolf and vampire in the same time. The body will not permit.