As far as I can see, it's impossible to make money transporting cars by train from the late 20th century onwards. Until now, I've assumed that this was one of those goods that was unprofitable on its own, but part of an overall profitable chain. There was however a change recently that suggested that such chains are no longer a good idea due to networked games.
On the other hand, cars are profitable by road and sea. They are also profitable by rail in the early to mid 20th century, as long as the cheap, slow locomotives are used along with the old car wagons.
So which is it: are cars unprofitable because of pre-networked games complete-chain-balancing, is car transport (like cooled goods) a victim of the sky-rocketing speed bonus speed for trains, or is it something else?