If you have Trainz 2009 sp2/sp3/sp4 or Trainz 2010, at the top of the screen in driver you should have something called QUICK DRIVE, if you go into this, you can set the time of day, right down to the nearest minute along with the type of weather you want, you can also add consists onto your route from this.
If you have an earlier version of Trainz, then in surveyor, go to file at the top of the screen, scroll down to EDIT SESSION, in there you will see a couple of boxes, go to the first box at the top and click on EDIT at the bottom of the box, you will then see start up options in Trainz, time, weather, change-ability in weather.....
Type into the time slot, which should look like this -
Time at start of session - 10:00
Type in the time you want, please note you must you use the 24 hour clock system to set afternoon times, example 1pm becomes 13:00, 2pm becomes 14:00, 3pm becomes 15:00 and so on...
Once done, click the tick at the bottom of the page and save, your session will start at the time you requested.
Hope this helps
Joe Airtime