It s all or nothing. These types of runs are the best use for high-speed electric trains, as well. They cost more to set up, but go the fastest. If you don't have enough money early, focus on building a sprawling freight empire. The military has a strict chain of command.
Troops are worth the most by far, and aren t much heavier than weapons.
This means you can move more of them at the same speed, or the same amount more quickly. Either way, it results in Munitions being the least lucrative for the profit-minded.