u/jraemr2

When you have more than one Train Delivery available, these are fulfilled individually. That is to say, any surplus passengers / cargo from one mission does not carry over to the next.

To give an example, I had two passenger Deliveries available, as per the screenshot. My first train fulfilled 198 of my First Class passengers, leaving 2 passengers on that Delivery and 200 on the second.

However, my next train dispatch, which had another 198 First Class passengers on it, only fulfilled the first delivery, and left the second delivery untouched.

So it will take some careful thinking to work out the optimal way to fulfil these missions.