I don't know if this will help, but:
The other day I was trying to "clean up" the PakSets on our old computer. I added a folder called "pak_alt", copied all of Pak64 ("Pak") into it, and then "weeded" out my Pak 64 folder (too many buses!!!!) The next time I started the program, I had a choice of either "pak" or "pak_alt".
So, apparently Simutrans doesn't care what's in a folder so long as the word "pak" is in the title. That gave me the idea to create my own "pak_us" set by just dumping the appropriate pak files into the folder.
I decided to check if anyone else on Simutrans is working on/interested in a pak.us, and wound up here!
Balance is a problem, so I plan to install Makeobj and edit some dat files. I am working on a quick-and-dirty spreadsheet tool to evaluate the cost per passenger/mile or ton/mile for road vehicles and trains. That will let the set balance internally at least. I am going to base running costs on kw, with decreases coming with advanced technology. For example, when diesel engines for heavy trucks come out in the 1940s-50s, that will decrease the running cost per km. Also, when "Aerodyne" type semi tractors come out in the '80s-'90s, that will reduce the running cost per km for a given kw rating.
"Gearing" will be fun to play around with too. This should accurately replicate the different size drivers on steam locomotives, different gearing on diesels, and different final drive ratios in road vehicles. Current plan is to use 100 kmh as a base for both road vehicles and trains. A vehicle should be able to reach this speed (just) on level road/track with its full load (road vehicles) or tonnage rating (trains.) Of course road/rail conditions limit this. Consistent with US practice, I intend to have multiple versions of the same vehicles with different gearing. For example, a standard 2-8-0 Consolidation steam locomotive (1-4-0 in European notation) will have a max speed of 100 kmh, a gearing of 1:1 (none) and enough power to pull a train of X tons to max speed (eventually) on level track. Another version will have a max speed of 50 kmh and a gearing of 2.00:1, for hauling heavy trains on steep grades and cheaper track. Or you could have several "Ten Wheelers" (US 4-6-0, EU 1-3-0) for general purpose (100 kmh, 1:1), freight (80 kmh, 1.25:1) or passenger (120 kmh, 0.8:1)
{Note: I have to do the math yet to figure the gear ratios accurately- these are guesses.}
The same will go for road vehicles. Since US manufacturers tended to build a "chassis-cab" which was fitted with different bodies for passengers, mail, freight, etc., the gearing for say an early 150kw truck can be changed to allow it to haul a decent amount of bulk goods (slowly) boxed goods more rapidly, and smaller (in weight) loads of passengers and mail at "highway" speeds (no need for 130 km speeds until the era allows the proper roads.) Rather than include every vehicle, I would rather have one generic chassis/cab per decade or whatever, with different versions for each cargo. (Not that I'd say no to complete sets of Mack, Ford, International, White, Kenworth, etc. vehicles.
OK enough for now. Will check back later with any progress I have made. Will do this for my own use, and will obtain necessary permissions before posting anything online. Would love to use the JNR steam locomotives as a base for a generic US set, since they look more US like than the BR sets.
