K&L has payware locos and cars for the StrasburgRR. I'm not sure about others.
Have you checked the DLS?
Searching on just "Strasburg" I see the following routes, sessions and equipment on the DLS:
<kuid:313505:1035> Strasburg 2-10-0 #90 V2
<kuid:14913:100001> strasburg 2
<kuid:313505:1249> Strasburg 44 Tonner #33
<kuid:365818:100002> Strasburg Railroad
<kuid:313505:1250> Strasburg 44 Tonner #9331
<kuid:14913:100002> strasburg 2
<kuid:313505:1434> Strasburg Combine Car
<kuid:313505:1034> Strasburg 90 SRR/GW Tender
<kuid:313505:1565> Strasburg SW8 #8618 (old trucks)
<kuid:313505:1037> Strasburg 90 GW Tender
<kuid:488277:100308> Strasburg v1
<kuid:313505:1492> Strasburg SW8 #8618
<kuid:262747:100003> Strasburg Railroad
<kuid:624227:100311> Strasburg Railroad
<kuid:872642:100041> Strasburg railroad
<kuid:717802:100039> Strasburg Railroad 2
<kuid:313505:1391> Strasburg Railroad
<kuid:313505:1393> Strasburg Railroad
<kuid:313505:1392> Strasburg Railroad 2
<kuid:313505:1394> Strasburg Railroad 2
<kuid:313505:1535> Strasburg Engine Sheds
<kuid:313505:1550> Strasburg J Tower
Some of the above may be updates using new kuids and not new versions for some reason.
There may have been a few threads about the Strasburg I can't remember right off but a search of the forums might prove interesting.
Bob Pearson