This is far off the V Scale Creations track, but since you guys are all so helpful...
I just downloaded an interesting shortline (and I DO mean short!) route called the Rye & Camber Tramway. Anyhow, I found an extra activity for it, but when unzipped it only contained a folder with the activity name. Inside this was an .apk file without a readme. I have never seen an .apk file. The Activities folder only contains .act files so I don't know how to proceed. The activity's author has failed to respond to my query.
What is an .apk and what do I do with it?
As for the route, I found Rye & Camber Tramway at UKTrainsim.com. Though its only 2 miles long, it has the most diminutive and charming engines, making it a fun and worthwhile little diversion, especially when one reads the purpose and history of the line - to shuttle golf and beach enthusiasts to and from Rye, Sussex and the golf course and beach.
Anyone who has an eclectic interest in historical steam and offbeat shortlines should check it out. You will have to dig around the UK site a bit to pick up all the rolling stock and its two steam locos.