Very curious to see what they end up doing. Are there six or seven trains? Only two are "refurbished" and heavier, correct? If so, they could conceivably do a 5 train operation until the others are ready to be refurbished, taking it down to 4. The problem area is at some point you'd have to run it with only 3 trains... either the three old ones, or the three new ones (assuming one is being refurbished at any given time).