I can confirm that unsubbing Russt_Bucket's cims got rid of the giants.

Thanks for the motivation to finally figure it out MessengerOfRage and CyberVibes. I might not have bothered without you.

smart thinking, it's well possible that it's just the cims undrerground view messed up.
and yes I use some cims from most of your links, I don't use the 50s set.

I unsubbed the listed Russt_Bucket's cim assets

https://sp.zhabite.com/sharedfiles/filedetails/?id=2947392375

and the ghost giants seem to have disappeared, though I I'll need to check when I create undergrounds in my new city. Will update.

https://sp.zhabite.com/workshop/filedetails/?id=2131809076

MessengerOfRage, and have all my metro lines be the same colour, lol?

I just resubbed to

https://sp.zhabite.com/sharedfiles/filedetails/?id=1415090282

After complaining about it too. Found I need my transport lines to have varied colours.

Did you download any cims? Might be a bad lod or something in one of them I'm wondering, though I've tried with unsubbed cims and can't figure which it could be.

I have these and some more.

https://sp.zhabite.com/sharedfiles/filedetails/?id=2596752042
https://sp.zhabite.com/sharedfiles/filedetails/?id=2159986339
https://sp.zhabite.com/sharedfiles/filedetails/?id=2717021596

And some from
https://sp.zhabite.com/workshop/filedetails/?id=2464209071

While compiling this list I found this!
https://sp.zhabite.com/sharedfiles/filedetails/?id=2083716756

So it might be Russt_Bucket's assets, if you got any.
https://sp.zhabite.com/profiles/76561198040296300/myworkshopfiles/?appid=255710

Probably best not to copy over your old folders and just start afresh that way you can rule out any config files that might be left over from old mods. I weirdly haven't come across this in my game so can't test to see what might be causing it.

hey I have them too, they are the same colour as the metro line, make your metro line off-white like the background in the traffic view and they become barely noticable... like giant metro ghosts.

It's not game breaking. I been playing with it for years, just sometimes I get pissed if it's there.

And copying over workshop folder will copy same things over, I think, but will try it someday. Thanks.

If it's an asset go here ..
https://docs.google.com/spreadsheets/u/0/d/1mVFkj_7ij4FLzKs2QJaONNmb9Z-SRqUeG6xFGqEX1ew/htmlview#gid=141983953
Click Game Breaking Assets
Check the list.

Follow this guide it'll remove everything even your workshop, you start clean all over
https://sp.zhabite.com/sharedfiles/filedetails/?id=1768579596

I found a similar complaint in reddit.

https://www.reddit.com/r/CitiesSkylines/comments/uq23ff/creepy_giant_metro_ghost/