Hi Brad,
I am not familiar with this engine so had to google it to see what it looks like. Looks a nice little shunter. What gauge are you building it?
It will be a long project as it is your first. The learning curve is very steep!!! My Simplex is my first large loco and has annoyingly taken me over three years to build. It was finished last October well into Covid restrictions. It has to wait for the club to open back up to have its steam test and in the mean time it will be fired up when the better weather comes. I have just started my next loco, 5" Sweet Pea, which I am posting elsewhere on this forum. With the experience of the Simplex I want this build to be alot quicker and am already moving at a decent speed. You will need plenty of patience as this is your first loco. Trust me things will go wrong but it is all part of learning. The problem I had was the longer the build went on the more impatient I got so the more mistakes crept in.
Though I am unfamiliar with the Penn Switcher I will watch your progress with eager anticipation. If I can help please ask though it appears there are several that have been built on this forum.
Good luck and happy building.
Cheers
Julian