[Mauzen]

Well, your function does not check for the closest one, but only if a tram is within the given range. So it will always return the id of the tram with the lowest vehicleid.
But you can do this with some extra lines:

pawn Код:

stock ReturnClosestTramID(playerid)
{
    new Float:nearest_dist = -1.0, nearest_id = -1;
    for(new c=0; c<MAX_VEHICLES; c++)
    {
        if(GetVehicleModel(c) == 449)
        {
            new Float:X,Float:Y,Float:Z;
            GetVehiclePos(c, X, Y, Z);
            if(GetPlayerToPoint(playerid, X, Y, Z) < nearest_dist || nearest_dist == -1.0)
            // You have to get any implementation of a GetPlayerToPoint function that returns the distance
            {
                nearest_dist = GetPlayerToPoint(playerid, X, Y, Z);
                nearest_id = c;
            }
        }
    }
    return c;
}

As you can see, you basically countercheck the distance with the currently shortest distance to see if the tram is nearer than your current nearest tram.