Welcome back! I'm not familiar with "pak-REAL-ECO-1900" - am I correct in surmising, from the name and what you have written, that it is a pakset designed to give highly realistic balancing of vehicle and building costs and revenues? Is this a new pakset from scratch, or an adaptation of an existing pakset?
By coincidence, I happen to be working on a similar project with the Simutrans-Experimental version of Pak128.Britain. I am in the process of obtaining real-world data on relative vehicle running and purchase costs from an informed source, which, although specific to the UK, might be of interest to you.
I have for a long time been in favour of making the economics of Simutrans as realistic as possible. Best wishes with your endeavour!