That's the easy bit, and the rest is Neroden's points (2)-(5). I have to admit I was just going to fudge it through a combination of educated guesswork on annual revenues and payback times, and good old trial and error. However, if anyone (Neroden?) wants to have a go at something more intelligent, then I'd be very interested in what they came up with, especially if it could also give some clues as to what values to give to infrastructure costs and maintenance.

OK. So this is what I'd do. :-)

For each vehicle, we have a good sense of whether it's a "short distance", "medium distance", or "long distance" vehicle. From this, you can use some educated guesswork to decide how many tiles, approximately, it *ought* to be travelling in an *appropriate* trip.

Enter that as a column in the spreadsheet.

We also know how fast it's supposed to run, and from that we can tell which type of track it should "usually" be using.

Enter the cost of that track as a column in the spreadsheet.

We know how long the convoy will be (we had to in order to compute (1) ), and from that we can tell how many station tiles it will take (another column in the spreadsheet). For freight we know how many stations are needed -- 2. For passengers we can make an educated guess for an "appropriate" number of stations (another column in the spreadsheet). Again, each engine is probably "supposed" to be used for either passengers or freight. From this we can figure the cost of station maintenance for the line.

Enter that as a column on the spreadsheet.

This gives all the entries, except factory units per month, needed to compute (2), (3), and (5). So add factory units per month as a column (you're just going to mess around with it experimentally) and put in the formulas to see what the results are for (2) (3) and (5). Then you can eyeball those results and see if the monthly profits make sense as you twiddle with the input numbers.

Essentially, putting those computations in the spreadsheet gives you instant feedback from your trial and error, and that's what I'd suggest. It's still trial and error for the input numbers, but with quick feedback without actually compiling the pak and playing the game. :-)

If you can tell me what the "expected use" of each road or rail convoi is (passenger/freight and short/medium/long distance), I can put the columns for those computation into the spreadsheet. Although I run OpenOffice.org so you may have to tell me what format to save it in if you run Microsoft products....

For (4) you should probably be running a different spreadsheet, just with locos (no waggons) and a couple of columns. Compute this as a "sanity check" to make sure you maintain the principle that $/kw goes up only if "something else good" like top speed also goes up. To avoid the "BR39 is dominant in pak64" problem.