Try taking a look at these frequencies. Put them in your scanner and see if anything comes up.
The most complete database of radio communications data
www.radioreference.com
The data base also shows 155.20500 analog for buses.
Scanner Frequencies and Radio Frequency Reference for Snohomish County, Washington (WA)
www.radioreference.com
Sorry I don’t know a specific answer to your question, I hope this helps.