Have you found this missing kuid? I need it as well XD If you have may I get a link?
Welcome to the forums!
We will never know if he ever found the kuid since nothing else was ever posted after answer...
There's a possibility that this asset could be replaced with something else if it is something like a horn or engine sound. If you want to try the steps below. They may not be the most efficient, but they work for me. Once you get the hang of it, it can be done in a matter of minutes.
A)
1) Go into Content Manager
2) Right-click on the asset, with the missing dependency, and view config.txt file.
You should be able to see the kuid number listed, and see what the asset is. Hopefully it's a horn sound or engine sound... If it is one of these things, do the next step.
B)
1) Search for a replacement asset. There are plenty already installed and on the DLS that should work, albeit not being the correct ones.
2) Repeat the process to view the config.txt file.
3) Write down the complete kuid including the < > and any colons

) characters.
C)
Go back to the original engine missing the dependency.
1) Highlight the asset again
2) Right-click and choose Edit in Explorer under the edit portion of the list.
A folder will open up showing various files...
D)
1) Open up the config.txt file by double-clicking on it. --- This should open up in Notepad.
2) Click on the Edit menu and choose Replace.
3) In the text to replace, put in the missing kuid,
4) In the replace with section put in the kuid you wrote down.
You should receive a message about the number being replaced twice.
E)
1) Save the config.txt file
2) Close the file.
3) Right-click on the asset again in Content Manager, and choose View errors and warnings.
4) If there are errors: Repeat the steps in Part D and check for typos such as the wrong number, or missing characters such as <> and :
If all is fine..
5) Close the folder.
6) Back in Content Manager, press CTRL+M to commit the asset and the engine should work fine in Trainz.
Good luck. I know this is a lot for a new user, but once you do it a couple of times it's a breeze.
John