Heard TG 11212 in Erie County yesterday, with reference to the "shed". It's listed as DOT Maintenance District 3 Chipping ERIE80 (05/21/2020) in the Wiki. That's Forest County, which I never heard in Erie before.
The PennDOT TG list is
not confirmed, there very well may be changes along the way, It's not cut in stone, and until we can obtain something concrete, That's the way it'll be. (It's what the wiki is for)
I've been thinking for some time that the Milling TG block and the Garage TG block may need rearranging/swapped somehow as well.
TG 11779 is currently being used and referred to by York units as D8 Milling not Garage as listed.
It makes my cerebellum ache.
If you could include any observed RID's in your reports, Small details can be a big help.

Take a look at the list,
wiki.radioreference.com
What do you think 11212 should be?

"Shed" by itself is a very loose reference and could be heard in any county in the state.
wiki.radioreference.com
Not sure where you got Forest Co from.. (Not enough info)
These are in District 3..
- 3-1 Bloomsburg (Columbia County)
- 3-2 Montoursville (Lycoming County)
- 3-3 Mausdale (Montour County)
- 3-4 Sunbury (Northumberland County)
- 3-5 Selinsgrove (Snyder County)
- 3-6 Laporte (Sullivan County)
- 3-7 Wellsboro (Tioga County)
- 3-8 Lewisburg (Union County)
- 3-9 Towanda (Bradford County)
Appreciate everyone's observations

It's how these things get worked out, Especially as more areas get radios..