I've made a patch that makes cargo-trains more competitive compared to passenger trains. It's running on my server (a slightly modified version, will change to the one posted below on the next restart), so feel free to try it out - http://haukinger.dyndns.org/ottd.
EDIT: updated patch - got switch in patch-settingsRaw material production can now get much higher than in normal OpenTTD. In the past, production was limited to about 2300 - now it can be 12500. This way goods-trains are as desirable in late-game as passengers. Production will never decrease. It will grow if you transport more than about 55%. If you transport more than 80%, large increases are possible.
Unserviced industries will close down. Normal industries start closing 3 years after the last train left, and raw material industries start one year later. Don't expect unserviced industries to live more than 5 or 6 years! On the other hand, the rate of new industries emerging is increased, too.
Loading/unloading-time is always zero, that is, if the train fits into the station. This way you don't need to build stations that are larger than the town they're serving...
Conversion from normal to electrified tracks with trains present is enabled, too.
EDIT: updated patch - got three-way switch in patch-settings
EDIT: updated patch to be at least syntactically savegame-compatible to normal ottd.
EDIT: updated MiniIN-diff according to official procedure
EDIT: removed easy_convert_tracks, changed to SLE_CONDVAR, savegame bump to 30 (normal) or 35 (MiniIN). can load old savegames. defaults to smooth economy.