Definitly #1 on my ‘wishlist’ for the trains since i’ve also had this for my (own scripted) trains in SA-MP (old San Andreas).
The problem here though is that the trains are not ‘server sided AI’, and until i’ve found a way to make
a (STABLE) reference to the trains from other clients (whom where not the ones whom spawned (“aka hosted”) the train) without generating server traffic with it I can’t do much (YET) about it
Only ‘solution’ now would be to keep sending the train coordinates from players whom are in range to the server, which in turn would keep triggering client events to update it (aka: Lots of unneeded traffic).
This is AS FAR AS IN KNOW at the moment the only possible way, since players for example can also ‘block the metro’ with a vehicle, so even 'scripting a fake blip will result in it loosing track.
BUT there is someone else also working on a train system, which we HOPE doesn’t have the despawn
issue, and if that’s the case i/we will fix the issue and see if it’s possible to make the blips again 