This is more of an on-going project instead of a discussion.  I moved it to the blogs:

http://model-railroad-hobbyist.com/blog/38816

The old cast zinc Roundhouse 2-8-0 does not quite fit into any PRR classification.  Heck, it does not even have the valve rods - just the yolk at the end of the slides. If I want to add detail then the valve gear is the most difficult.  It would be nice if there was some prototype with inside Stephenson gear and cylindrical valves.

 Fortunately, the Pennsy modified anything that rolled.  You could stick pretty much anything on there and if it has a Belpaire boiler you could say it is a PRR engine and there was a prototype.  Sometime.

My plan is to add detail gradually, not file everything off and start with a box of parts. I don't want a "garage queen" waiting for that last bit of detail before it runs. Here is the original Roundhouse engine.  It has a can motor and moves very nicely. I plan to emulate an H6 series with inside valve gear. Road number 3816 (below) is pretty close.

• Add yolk and inside valve rod
• Add air piping under the footboards
• Replace the handrail with one that loops over the top.
• Add wire to the bell and whistle
• Paint an all-over weathered grey
• Then decide what else to change

Many of the H6 series originally had inside valve gear and rectangular sliding valves, like road #5.  Some H6 were upgraded to new steam chests and cylindrical valves like road #3816.  Some were built or rebuilt with Walschert outside valve gear.   The Roundhouse will be numbered from this database.It could even be #3816 before the air tank was moved.

Here is my other Consolidation, a spiffy brass H9/10.   Once the Roundhouse is piped and painted they will look like old and new versions of similar classes. I am aiming for a family resemblance, not exact copies.

Prototype images.  

PRR H6 #5

PRR H6 #3816