I had to make an account just for this one…
The key to TF is hubs, not Loops.
Forget Loops except for inside the city with 2 or 3 Bus or Tram stops just to drive station use.
Bus and Tram between cities works fine for point to point. After 1915, the 1st high capacity TRAM I can turn 1/2 a mil a year on a really good line, 300K on an average one. Bus routes turn good coin after 1903 and don’t look back, they can remain profitable for a very long time.
The key to making big money in Passenger trains is to use the same mentality as Bus or Trams while taking advantage of the added lines the stations give you. What determines where and who gets rail is elevation. Usually, each corner city has 2 or 3 natural partners and each central city can make a nice flat line to 3 cities, sometimes 4 or 5.
If you look at your map in the OP, take one of those inner 4 cities and plant a 5 rail station there. Run rail to 5 cities, point to point. The line runs from the station to a station at the other end. That station may also have 2-5 lines depending, all sending trains point to point to specific destinations. In the end you end up with a Web, not a Loop.
After awhile with faster trains you can grow a point to point to service a stop in the middle, especially if the middle stop is a big city. You will need to run multiple trains however with good sidings, so maintenance and transit time become much bigger factors. Running point to point I never have those issues, everything is right there to see and very straightforward. I never have to worry about people waiting too long on a platform somewhere, they are ALWAYS on a train going right to where they want to go.
Time this to when the General Loco becomes available and use 3 or 4 cars depending on city size. One single train will usually turn a nice chunk of change on a single rail. When a line grows to where you have people waiting, add a couple passing sidings and signals and add a 2nd train. Smile as money rolls in…
I particularly like the M-300 and the Metro liner. A train of 2 or 3 M-300s can rake money in vs the maintenance of a fast steam engine and cars. The Metro liner is the same, they’re too easy to make a killing running point to point. I don’t use any of the steam engines besides the Mikado on a whim.
All this said, my best games are ones that use no rail simply because it makes it too easy to crank dollars off a good line. I love using Trams an Buses between cities and nickel & diming my way to millions. That and deriving perverse satisfaction of doing well with wagons and trams and buses oh my.