Checked out a lot of my very old arcives from different sites i downloaded long time ago, sadly to find they were all faulty and missing items but were from 2004 / 2006 period, best you can do is replace them with the ones from Ptram but even some of those are faulty as well but still got a few, there is more Utopia trams like the ones on DLS in different liveries, 4 x 6 GT6, 4 x GT8, 3 x GT8ZR but some do Have Polish markings GT6 631 is Jagermeiter, any that use a Cup in between units don't seem to connect right
If you want to go really old Polish type 1, the Ringhoffers with trailers, type N, Type 4N, Heidelburg, Type PN (be careful of sharp curves with this one for Works there is a N type as Track Cleaner and Overhead car.
Tom
Hope this helps
Tom