Add Tier providing errors

[geovolve]

Hi all,

I've build a new UN model, and am at the stage of Adding Tier Groups and Tiers that mimic the Communications foundation model.

The 'Add Tier Groups' function works fine, and I can create them. However, when I attempt to add a Tier to any of the groups, I'm provided with this error msg:

ERROR 002136: The subnetwork field name already exists but does not match the expected field properties.

I get this response whether I use ArcPro interface or python commands.

I've checked many names, and the field definitely does not exist. This seems to be a bug and it may be related to UN and Pro versions. I'm using Pro v3.5.2 and have built a UN v6 (as customer has v11.3 of enterprise and I'm avoiding the Field Maps support issue).

Any advice or tips?

[gis_KIWI4]

@geovolve - I don’t this may be stopping you from using the tool but have you checked this out? 

“Tier groups are not used in the modeling and organization of tiers in partitioned systems, such as electric, and do not apply to telecom domain networks. Sector organization of these industries is modeled at the domain network level. To learn more, see Traditional domain network properties.”

https://pro.arcgis.com/en/pro-app/latest/help/data/utility-network/tier-groups.htm#:~:text=model.-,T...

[geovolve]

@gis_KIWI4 This is actually for a Fibre domain, so is hierarchical.

The foundational model for Communications has these properties, so just trying to rebuild them. Thanks for the feedback.

[MikeMillerGIS]

Can you post a screen shot of how you are filling out the GP tool?

[geovolve]

@MikeMillerGIS 

Screenshots attached, and below is an extract of the tool messages.

Could this be a limitation of using a mobile GDB?

This did work when using ArcPro 3.3.5 with a v7 UN

Add Tier
=====================
Tool Path

Input Utility Network <path to mobile GDB>
Domain Network Communications
Name Cable
Rank 1
Topology Type MESH
Tier Group Name Cables
Subnetwork Field Name CableSubnetwork
Updated Utility Network <path to mobile GDB>
=====================
Messages

Start Time: Friday, 22 August 2025 10:49:55 am
ERROR 002136: The subnetwork field name already exists but does not match the expected field properties.
Failed to execute (AddTier).
Failed at Friday, 22 August 2025 10:49:58 am (Elapsed Time: 3.73 seconds)

[geovolve]

@MikeMillerGIS I also exported to an AssetPackage and then applied that AP to a new Mobile GDB - same result.

[geovolve]

Further info @MikeMillerGIS 

I uninstalled v3.5.2 and went back to v3.3.6 - Add Tier works on the same GDB.

[MikeMillerGIS]

I tried to repo it and have not been able to.  But at least you got a workaround.

[geovolve · Accepted solution]

For anyone else with the same issue, I had trouble repeating the resolution, but I believe it was resolved by:

- Downgrading to ArcPro v3.3.6

- Exporting Mobile GDB to an asset package

- Applying that asset package to a new mobile GDB

- Executed tools or scripts to Add Tier Groups and then Add Tiers

It was a weird one though and may not apply for anyone else.