RayofSunshine, I don't want to confuse you with my advice as well. But "any freight", and "any express" are in my opinion a type of "custom consist". As always, a discussion comes down to what you are doing to make profit and what you are doing to make the goals and win the game. Basically, "any cargo" is going to make more revenue while "any express" will ensure that all passengers available at the station are transported helping towards the goals. As always it is up to the player's strategy. Normally, concentrating purely on making money for the first few years pays off in the long run as you can expand quickly and have a solid revenue base for future expenditures. Then with a good size network which will produce passengers fairly quickly start building Hotels and making Express-only routes. I tend to not make a sudden switch, but gradually spend more on the goals and less on investments for pure profit. It's a balance thing.
If there are no passengers wanting to travel it doesn't matter what settings you use, none will travel. As far as I know the game only checks for whether a train is stopping at a station regularly and which towns are coming up on its route when deciding which passengers want to travel (as you have noticed many aren't looking to go anywhere). It doesn't look for use of a custom consist or if the trains on that route is Ultra Cool (this affects revenue the passengers will pay however). The more often that train/s travels on a route, the more likely the game will give some passengers from a stack a desire to travel on it. Once a route is established by frequent service you will see some passengers waiting to travel that particular route. The more passengers you haul, the lower the fee paid by passengers traveling that route, but remember that Hotel and Restaurant revenue is necessary for the goal and since it is high in this scenario it will easily make up for any train losing a little money. In this stage of the game, as long as the whole route setup is break-even it can be a good investment in terms of the medal (remember that with passenger routes it takes a little time for a route to be established, so after 2 or 3 years). It's a matter of checking the passenger map a couple of times every year (later in the year is better) to see where there are demands for passengers to travel that you aren't fulfilling. And buy any trains you need.
When I played the second time with freight, I mainly used "any express" trains. The others were "any cargo". I only had the "any cargo" trains on particular routes. Mainly between the towns which have warehouses and industries supplying cargo. I put some on selected routes to scenic sites, the idea was that these were short routes mainly in the west of the map early on to distribute warehouse cargo there (started with a station in Camelback and hauling warehouse freight there). By limiting these "any cargo" trains to shorter routes I saved on fuel while increasing the cargo density in those portions of the map which means that price swings (read profits) will be higher than if the cargo was randomly distributed in small amounts all over the map.
The main argument for using "any express" trains is this: under a certain price point (depends on strategy, but let's say $10k per load) it is actually detrimental hauling freight. Either it is stealing supply from industries that will now suffer production irregularities (not such an issue on this map with little industry) or for consumer cargoes (Meat, Goods, Cheese, etc.) there is far more benefit from less frequent service when that same haul could give you $20k per load (less a small amount of cargo which has been consumed) while also costing less in fuel and train maintenance costs as less trains are used to theoretically maintain a higher price point. As you haul plenty of passengers especially on short trips, their price point will go below the price point at which you want to haul freight ($20k for this example). A train on "any cargo" will now mainly fill with low value freight instead of the passengers you want to haul. Increasing the number of trains will hurt further as more freight miles will be hauled at lower revenues and higher cost.
As always, this stuff is a little of the theory and in practical terms it can seem to be only a small thing. Didn't want to confuse but maybe some new ideas.
I heard that.
Any comments? 
