The days pass very quickly in the game.

[Rick Galli]

Hi, the days pass very quickly in the game... the trains take three months to load and unload... How can I slow down the days?? excuse my bad english... thanks!!!

[beeurd]

There is a daylength patch if you know how to install such things.

If you search the forums you should find it.

[Andrex]

In other words, no you can't change the day length with the official OpenTTD releases.

The patch for that is here and seems to have been abandoned in 2009. But from what I read there it has some bugs due to implementation difficulties, is not as easy as it sounds.

[YNM]

Problems are with month length for industries production counting and days for vehicles servicing from what I remembered.

[kamnet]

Some of the patch pack maintainers continue to use and tweak the patch.

[Alberth]

Hi, the days pass very quickly in the game... the trains take three months to load and unload... How can I slow down the days?? excuse my bad english... thanks!!!

The game is not a simulation, it's a game intended to be fun to play.
All scales in the game are adjusted to that goal.

You don't really want to wait a full 48 hours or so before a ship is loaded, right?
Transport in real time is very boring to watch.

While it may feel a bit weird to have such short days, it isn't really a problem. To play an entire game (100 years game-time) without fast-forward will still cost you about 24 hours non-stop playing.
Just ignore the day number, and only use the month part.

[kamnet]

You don't really want to wait a full 48 hours or so before a ship is loaded, right? Transport in real time is very boring to watch.

Well, it might be boring for you, but some of us weirdos DO like watching this stuff all day.