Due to a calculation error, some corrections have had to be made to the previous 2 posts, published last week (The cost of transport and fare setting) and earlier today (Follow up to fare setting). The error involved mixing up the average length of trips for buses and ferries (they were swapped around the wrong way), and a rounding error for train fares per passenger km.
The adjustments show that the operating cost per passenger km is actually the same for trains and buses, but remains higher for ferries. Meanwhile, the fares paid per km now see a much greater disparity between buses and trains. As a result, the initial conclusion that multi-modal fare integration between only buses and trains remains, given that the have almost identical operating costs per passenger km (previously there was a small disparity).
However, this will become harder to achieve politically, given that the increased disparity in fares per passenger km mean having to increase train fares by 50% relative to bus fares. This could be achieved by a combination of bus fare reductions and/or train fare increases, and this in turn could be achieved by the removal of discounts for trains (such as the heavily discounted periodical tickets) or expansion of discounts to buses (such as the off-peak travel discount currently available on trains only).
As before, the second post discusses many of the limitations of the assumptions that underlie this conclusion. Although the figures have changed slightly, the arguments and ideas discussed in those posts, along with the comments, which have proven to be very interesting in their own right, remain worthy of consideration.