for(TrackIter i=train.get_block_allocator().first().track_iter(); (target_tracks<2 && i); i=i.next())
{
if(i->get_block().get_train()!=&train)
for(TrackIter i=train.get_block_allocator().first().track_iter(); (target_tracks<2 && i); i=i.next())
{
if(i->get_block().get_train()!=&train)