It seems like, with very few exceptions, it is always better to use a "regular" engine with passenger cars than it is to use a trainset dedicated to passengers. Doing so allows carrying more passengers at less cost, rarely more than $4 or 5 per km. The dedicated passenger-only trains (ie, the ones that appear in the passenger trains tab in the depot) typically have extremely high costs $10 or even 15 per km (!) to carry fewer passengers at similar speeds. Take, for example, the Pioneer Zephyr, which claims a top speed of 180 km. Not only can it never achieve much over 100kmh as a maximum speed for the purposes of the speed bonus due to its low power, but it will never turn a profit, not even with the speed bonus at its year of introduction. The Pioneer Zephyr is perhaps the most extreme example I've noticed, but there are many vehicles like it in the game, such that it is almsot never worthwhile to run the powered trains from the passenger trains tab. Am I simply misusing these vehicles, or is it just a balance issue that has not yet been addressed?