Except that you now effectively have cars that are twice as long and articulated in the middle. If one half of the double-car is damaged, both have to be taken in for repair, and both have to be transported and handled as a unit.

Presumably, the previous single-car size had already been optimized for pre-toilet criteria, and changing that by a factor of two probably massively screws with at least some of those criteria. It's hard to believe that the costs savings for having half as many toilets significantly outweigh those other factors.

Not sure. Essentially a new class of 'car' was created, twice as long and roughly twice as expensive. If the cost of dealing with the larger cars was non-zero, then maybe it was break-even. Its premature-optimization at its finest I think.

Yes, but there is half the number of cars in each train, so the doublings cancel out. That said, the overhead of larger cars could still be a significant factor.

Assuming the original cost-cutters decision was correct, it isn't twice as expensive.

Absent from the story is any mention of cost-benefit analysis. I'd agree with the unnamed director's decision to eliminate every other toilet if there was evidence that, in the long run, it actually did cost the railroad less.