Yesterday, I updated and fixed the town growth code on the devel-new branch to incorporate (with some slight modifications) Neroden's town growth code from Standard. I had originally planned fully to rework the town growth code for the next major release of Experimental, including localised growth and full integration with the new features of the passenger generation code, but this is not likely to be practical, and I wanted to find a way of fixing the problem in which towns grow far too quickly to make a long-term game viable (as was demonstrated in the last Simutrans-Experimental online game using the 11.x series). One of the problems in the previous code was that the settings in simuconf.tab for adjusting town growth rates were not functional: this has now been fixed.
I should be very grateful if all those who are playing self-compiled versions using this new town growth code could let me know whether the growth settings have been calibrated sensibly. They can be adjusted using the advanced settings dialogue (the "i" key in Pak128.Britain-Ex) in game.
Does this do anything about the road diagonal removal bug? It really screws up road transport easily when it removes important city connections and suddenly road vehicles have to take vast detours or even get stuck totally.
This does not fix that, but I think that I fixed that separately a while ago; can you re-test?