void checkGems()
{
foreach (Train t in trains.trains)
{
int[] train_coord = t.current_tile.getPos();
foreach (Gem g in gems.gems)
{
int[] gem_coord = g.getCoordinants();
if (train_coord [0] == gem_coord [0] && train_coord [1] == gem_coord [1])
{
gems.removeGem(gem_coord);
score++;
}
}
}
}