Switchers up here stayed in PM lettering for some time...well into the late 60's. By the time I started in 78 they were all C&O and you had to have a book to figure out which ones were exPM. I remember seeing them though in our semi-regular trips to the yard back in my formative years. Whats neat is the time I spent down at that yard as a kid then retiring from that same place at 60 years old, 8 plus years ago.