Pete - it was the motor … stopped working. I removed it from the chassis, and applying power to the terminals didn’t help. The brushes were reduced to wafer-thin discs of graphite.
I stripped the chassis down and I used it as a free-rolling dummy unit for a few years. Last winter, I subjected the shell to surgery and, armed with a few prototype photos, converted it into a B unit sitting between two Rapido sound-equipped FP9A’s pulling The Canadian. Two weeks after completing the conversion, serendipity struck … my hobby shop had just put a used dcc-equipped Intermountain B unit on the shelf (perfectly matched CPR burgundy) so I snapped it up.
These days I usually just run the three factory locos in consist. Occasionally I’ll put my fabricated B unit in the mix for some variety, but to my eye, an ABBA consist pulling just 10 cars looks like overkill.
For me, it’s nice to see that my original Postage Stamp set is still useable, and providing enjoyment, 50 years down the road.
And oh, one other thing - I also still have the box that it came in. It’s holding an Aurora Postage Stamp N scale Greyhound bus set from the same era (it too still works - I set it up for the grandkids to run around just a few weeks ago).