No they are not the same.
The z-500 & z-750 are 4 amp max.
The z-1000 AKA Z Controller is 6 amp max
So while a z-1000 can be used with any mth transformer brick. Using one of the 4 amp controllers with a z-1000 brick could damage the controller under a heavy strain. In other words while it could be fine operating an engine pulling freight cars, it may not be while pulling passenger cars and especially subways.