Originally Posted by
wxguy
Negatron. For E500s, it's the origin-to-destination mileage that counts, as long as legal connections are made and the O-D upgrade can be cleared at once. If the segments are cleared individually, then it's point-to-point-to-point mileage.
In this case, the question would be is if PIT-ORD-EWR is a legal routing (isn't that known as backtracking?).
If its a legal routing, then only 1 E500 would be pulled.
If its not a legal routing, then 3 E500's would be pulled.