Fine Tuning the Bonus Routes

I spent last night looking into the problem with bonus routes that I mentioned in my previous post.  I wrote spreadsheet to calculate the likely incomes from various routes in various phases of the game.  A particular aspect of 18GB is that the dividend distribution rules create ledges when a company's income reaches a new multiple of five or ten, which complicates the assessment of the effect of bonuses.  If a bonus of +3 takes an income from 17 to 20, it affects the income in a way that an increase from 15 to 18 does not.  This gives me more scope for fine tuning but makes the design process harder.

My main concern from the last game was that the London to Hull bonus was too high.  Combined with the intrinsic income, it made Hull worth 8 for a train from London, which is more than other cities in the area such as Leeds or Newcastle.  This was distorting the routes too much, so I have reduced the bonus from +4 to +3 and also reduced the income distribution for Hull itself from 2/3/4 to 2/3/3, so that in the final phase it is only value 6 to a train from London.  This might make it a worthwhile endpoint but also allows other options.

The main aim of the bonus routes is to encourage companies to build routes to places that otherwise might not be worthwhile.  One key example is London-Aberdeen, which can score over 50 with a single train with the bonus in place.  Two other important cases are London-Plymouth and London-Holyhead, both of which were important routes historically and which would be pointless in the game without the bonuses.

For consistency, I know have almost all off-board areas have the same income distribution as equivalent on-map cities -  2/3/3, 3/4/5, or 3/5/6.  This helps to make certain bonus routes useful in the early game but less so in the later game.  The Plymouth and Holyhead bonuses are still high; it will be interesting to see whether they are too high or whether they work.

There are now just two exceptions to the general consistency of incomes for off-board areas. London itself, at 3/5/7, is marginally more than the other conurbations in the final phase (despite being much bigger historically).  The West Highlands of Scotland, at 1/2/2 are less than any other off-map area, being little better than a town.

This all looks good on paper.  The next game should show how well theory transfers into practice!