Obviously the optimum train length will change depending on what trains are available, the cargo types, and maybe even how hilly the land is. But what train lengths should a beginner pick for some common scenarios if he/she doesn't want to do lots of math to calculate the best size?
The ideal answer would address common scenarios such as:
- A passenger line with early train technology.
- A freight line with early train technology.
- What changes when you get to electric trains and beyond?
As well as intuitive ways to extend those rules of thumb to different scenarios and general guidelines about train length to consider when building a large rail network.