see this post:
http://hookedforums.com/a/viewtopic.php?t=1547
i've changed the UK standard map
resulting in this version.
- THE UK Map (standard from the game)
+ addaptions:
+ inputoutputratio set to 0.14 for main goods (production to a secondary good is not changed)
+ inputoutputratio for passengers and mail set too a much lower value
+ Mapsize is changed from 10 to 15
+ iturnspermonth set to 36 (for scenario goals and for more effect of trains)
for the rest i didn't changed anything because i wanted to keep this map as the standard one, except the production, to show the difference
Also the AI isn't loosing his head, it could be he's even playing better because of his approach, but neither i changed settings here
The scenario goals are still possible, i've tested it without a problem
have fun and surely try this out!

ps: i will change probably more to this map, as maybe a test but also to achieve in my eyes, a better intresting gameplay
ps2: plz, let me know your reaction on the impact of this change...
ps3: if i've made somewhere a fault (this could have been the case with changing the mapsize and so replacing the cities, or maybe a texture problem) let me know...

INSTALL NOTES:
JUST UNZIP the file in USERMAPS!!!