I tested something, i could drive with train in circle on tracks2.dat in both directions.
So the train ride will be connected from start and end point.
tracks2.dat seems to be unused for default train spawn, but available for scripting. I never saw a train on tracks2.dat. Maybe i'm wrong
tracks3.dat is SF Tram
tracks4.dat have for a part the same track like tracks.dat, it seems also to be unused for default train spawn, but available for scripting and don't have stops at stations
The coords of both tracks, tracks.dat and tracks4.dat are listed in same order, beginning at north/east, then passing LS unity station, then Market station and then SF Station
And the mysterious ride, i mentioned, from SF Station going straight to very east of San Andreas, is, because start and end points of tracks4.dat will be connected
The Stations of coord entries of tracks.dat are marked with flag 1 at the endgtamodding
says "Station, 1 - left side exit, 2 - right side exit"
-1944.1 139.877 24.7148 1
LS market station
814.997 -1366.51 -2.668 1
LS unity station
1725.12 -1953.81 12.5503 1
Turn the map a little bit in 3d view, then it shows also the points between Unity Station and the exit of the tunnel
But I also want to make some regular trains spawn on these tracks for debugging purposes.
When i go to SF station or LS market station or LS unity station, then a train arrives and stops
So i don't understand your request
With scripting is possible to spawn any train at any point of any of these 4 track files in each direction i want
But track4.dat is overlaying to track.dat, so i can't say, spawn it on track4.dat or spawn it on track.dat