Note: The below was originally written as an email to a friend just starting out with an 18xx design project. I’ve copied (and lightly edited) it here for preservation.
More directly, I think you are losing sight of the game, or at least where the game lies within the larger system.
The 18xx are fairly simply structured from two and a half almost-complete games bolted together. There is a spatial route building game and a stock market game, and they are glued together with a creative destruction technology race to make one complete game. Each of those components is damn near a standalone game in its own right, and certainly other games have been made from just those subsystems (Greentown, Lokomotive Werks, etc), but at the end they are just mostly-isolated subsystems with the actually interesting bits in their connections to each other (the players sit in the connections).
The internal structures created by that glueing process are also boldly simple:
There’s an evaluation function which each company uses to generate a number using as inputs the network on the board and the trains in the company, and we call that evaluation function “running trains”. You can get all sort of complicated here about the details of track and tokens etc, but at the end of the day there’s just a function that does something and returns a number that is input into the stock market game. All the rest is internal implementation details. Sometimes the number is a bit special in that it expresses a liability for the president (emergency train buy), but it is still just a number communicated from the evaluation function to the stock market game.
The stock market game takes the numbers that the network game generates and thence changes its own numbers in well known ways.
And, as a back-flow, the stock market game moves some of its numbers back into companies (withholdings, etc) via the creative destruction technology race glue to change the inputs to the network evaluation function (train purchases and rustings).
And thence of course those new numbers go into the stock market game and so forth.
And so we have a triangle: The network game informs the stock market game which informs the technology game which informs the network game which…etc. And the players sit in the middle fiddling with the dials in all three sub-games: moving the numbers around in the stock market game (shares), moving the numbers around in the technology game (trains), and moving the numbers around in the network game (building/changing routes), all while the loop keeps cycling as a feedback loop, round and round and round.
Which I assume you already know — there should be no surprises there — but you might not have articulated in such a stark format. More usefully and more to my point, what this really basic deconstruction does is to highlight where the game is. The game is in the players fiddling at those three key junctures in the triangular feedback loop while the game spins underneath them:
Players can fiddle with shares
Players can fiddle with technology
Players can fiddle with the evaluation function inputs
And that’s pretty much it. Everything else is in the feedback loop orchestrated by the rotating sequence of SRs and ORs stepping around and around the feedback loop and relentlessly driving the game forward.
What this means however as a game designer, is that it outlines where your interests and activities lie. In order to do something interesting in the 18xx world you have to either alter one of the three interaction points (shares, technology, evaluation function) in a way that substantially changes player concerns, or you have to alter the properties of the feedback loop itself (1880 did this latter with its new intertwingled OR/SR model; 1846 did this by fundamentally changing the feedback loop of money with how its incrementally capitalised companies work; 1860 did this by allowing entities to enter, leave, roboticise and re-enter the player interaction-space, etc etc etc).
My general sense is that at the litmus-test level, in order for any change to be interesting, it must substantially affect at least two corners of the triangle in ways that provide both substantial opportunities and problems for the players to address. Just touching one corner isn’t enough, as that’s almost instantly an internal implementation detail rather than anything materially interesting. And so you need at least two player touch-points to change in a way that’s substantial and different and interesting.
But more usefully (I hope), that deconstruction provides a set of analysis tools and litmus tests for your candidate changes. You can look at any candidate change and ask how it affects those three contact points, how that change to those contact points significantly alters the three stages of the feedback loop and thence how it changes the player’s competitive lives. And if you come up with a good answer, your idea potentially has some good legs under it, and if you don’t come up with a good answer, then your idea is more likely just shuffling the deck-chairs around.
And, shrug, I find that useful, as it sure weeds out a lot of options that fiddle little numbers inside one of the touch points without actually doing anything structural. Oh look, now this little internal number that isn’t actually a primary contact point is a little larger or smaller or different or has little brass bells and is painted red…but everything else is exactly the same…and…this…is…interesting…WHY? I do that a lot, and then I slap myself on the back of the head, say “Doh!” and move on.
PS BtB this deconstruction has an amusing side effect of also dropping out the four basic types of 18xx by extrapolation — which is kinda cute and unexpected (by me).