Oh, interesting. Something like this is would definitly helpfull!
How is it meant to be used, in general map creation or as a negativ multiplier in growth, can it implemented in a existing game (doesn´t seem to have an effect)?
I used it (beta2.0r707) with map generation and it seems to work fine in all climates, producing maps with rather small villages, most <100, allthrough there are problems with the editor: random towns doesn´t work at all, manually placed towns have allways a population of 0, even when enlarged. (Ottd r16269).
I started to play some OTTD pre 1920 game recently, starting in 1830 with NARS2 and eGRVS, now I´m at the year 1910. I think it´s a great fun to play with these early vehicles. Insanely fast growing Cities is one of the worst problems. You just can´t handle so many passengers and since there are no special old town sets it doesn´t look really good.

- Jamestown & Hetfield RR, 3rd Jul 1869.png (254.91 KiB) Viewed 4671 times
At the same time I have a lot of tiny villages on the map served by choaches, it would be good if they might grow a little faster and offer enough cargo for a small scale service.
Therefore a general reduction of population and generated passengers (and mail) might offer a nice fix to start with but not a fully satisfying solution.
It´s pretty much the same thing with freight. Allmost all industries produce far more then you can possibly transport before a certain year, which is around 1870/80 on this particular set. The screenshot shows what you need to haul away the monthly production of this farm, it doesn´t take in account that the 1960 train moves four times faster than the first. In eGRVS it would be about 24 horse drawn cars.

- Murphy & Co., 1st Jan 1984.png (96.3 KiB) Viewed 4597 times
ECS industries often have a small production even when they get now raw materials, this is about everything you would need for a small service in early years. The problem with very low but variable production is, that it´s close to nothing and with no production the industrie would close down. So what would be desired for an early industrie would be a small but rather stable output and that some industries should only appear or replacing others from a certain date onwards (planed in FIRS).
Since untill now I haven´t read much about pre 1920 games in the forums I wonder what other players might have expierienced.