If it's via some obscure rule which takes hours of head scratching to work out, that's not really what I want to see.
First, it isn't single rule. It is a set of rules, driver commands, and "path controlling box". Their list
is here. And it doesn't pre-allocates paths. It allocates paths "on the wings" in driver mode, as i've told, according to rule events (as you know, using "time check" rule it is possible to make time events, but it exists variety of other rules

), to driver commands or to path interfaces (
http://trainz.org.ru/mediawiki/images/9/90/Браузер_элементарных_маршрутов.jpg). It can't pre-allocate the hole path for the train from the beginig station to the end station, it allocates the paths only from one signal to the neighbour signal (shunt paths from signal to signal of the same station). The configuration "when and where to apply paths" is up to user. Of cause, in it you can ask (configurate a rule/ a driver command to ask) to set path not only "from signal A to signal B" but "from the signal in front of the train with red light, set a path through a free track with lowest priority not lower than 3 and not higher than 5" (in the case you have set those priorities for all paths of this signal).
By the uninitiated view, it looks like this -
It has no graphical interface, and it demands time to setup signals (they have to be allocated into station and block groups, only one signaling system supports this), correct position of some junction levers (they have to be placed in front of the track spline points), generate "train paths", set priorities for those of them, that are "automaticly chosen" by commands or rules, and finally configure sets of driver commands for "traffic" (multiplicated combination of "set path from signal with prioriries ..."+"wait for time"+"drive to next signal with speed **" for exapmle) and sets of rules for "player activity". It is uncomparable with clicking in the 2D scheme "here we want to see a startup position of the traffic train # 4 in 6:30 a.m., and here we want to see its final position in 7:55 a.m." by its difficulty. But here you can add "a train beyond the shedule", configurate it for different set paths according the time (not to interfere with shedule traffic trains) and finally add a random time of departure

. This is much more interesting then "I see the same train in the same time in the same position".