While playing cargodest, I noticed a lot of negative incomes from hierarchical network constructions, arising from the fact that cargo take a big hub as next stop, then need to go back in total distance, or take some slow transport which reduces the cargo value below that what was already paid.

To fix this, I wrote a patch that alters the transfers such that only a certain percentage is paid to a transferring vehicle. Essentially paying off half the total price to the final vehicle in the chain which would normally have to cope with the negative incomes.

You can get a copy of the original patch here: http://www.tt-forums.net/viewtopic.php?f=32&t=41420 - it bumps the savegame so you will need to fix that if you use a different revision for patching