I believe it depends on the Bishop's wishes as to if they can or can't use engines, and some (those that have milking operations) often have electricity in the milk parlor to keep the milk cold.
The Amish that I'm familiar with range from "old order" (old testement) followers (these are the no electricity, no motors, ect.), to steel wheel Amish on to rubber tire Amish.
Steel wheels are one thing, what always kills me is to see the younger kids, mostly girls, running a power push mower barefoot.
There is a gray area kind of in between the Amish and the Mennonites where many reside as well, where they aren't quite Amish and really aren't Mennonites either. Although there are many similarities between them.