I confess I would love to see bigger trains.
I know it messes up the economy.
But we already have different paksets, with different economies.
I use pak128.Britian to this day, because pak128 was to hard for me to start, then I got addicted to the graphics.
I know it messes the scale.
But we already have a non-to-scale game.
The bus/horse/block example above is a good one.
I know it can ruin industry balance.
But we already have a non-balanced industry, with order system that needs improving.
Only I know the problems I have with a car industry ordering steel from the other side of the map: in one moment I have 10 trains stopped, in another I have 10 trains moving, full of steel, entering other lines and turning a line that has a 10% usage into 80% of usage, which is a nightmare.
Here I leave you an image:
Direct link: https://s25.postimg.org/rdqr60ftr/Simutrans_3_Trains.png
My map is 2056x2056, at the present.
But I started with 1024x1024, and this is where my main lines and money is made.
The rest is a WIP (Work In Progress).
As trains have a limit of size, and consequently of number of cars to haul, I am obligated to buy a huge number of trains, and build two way transit, which is not very realistic, is it?
The big number of trains is due to the demand, and the two way transit is due to the demand system of factories, as the trains will take freight to only the first two factories, and then will go empty until they reach the original factory again.
I had to build new factories on the way, all linked, to make the run profitable.
In this image you can see three trains:
a) Vehicle #1883: Takes Oil to be burn in the electricity plant, and returns empty, from bottom to top of the map, approximately 1024 tiles;
b) Vehicle #5686: Takes Petrol across the map, to be distributed by trucks to local Petrol stations, in a Clockwise motion;
c) Vehicle #650: Takes Petrol across the map, to be distributed by trucks to local Petrol stations, in a Anti-Clockwise motion;
When #1883 returns from the Electricity plant, it shares the line with the #650 train, to save construction costs.
But, this results in a high congestion zone, mainly due to the great amount of trains distributing Petrol across the map.
I also have a Car distributing train line, much like this, with Clockwise and Anti-Clockwise motion.
With longer trains I would not need this much trains, and will save on congestion problems.
Also, the cars limitation on trains is not linear.
Petrol and Cars have a lower limit than Bulk cars.
So, I vote for longer trains!