Drag driver
Quite simply, the drag driver tool enables a scenario writer to click on the driver icon on one loco within the scenario editor and drag it across to a different loco. All instructions applied to the original loco will be carried over to the new one. This is very useful if you need to swap locos for any reason.
I like this a lot. Doesn't replace RW-Tools but complements it. Easier to use for newbies too.