I have disassembled and reassembled locomotives countless times. I have tinkered, fiddled-with and messed-with more miniature things than I can remember. Sometimes, I find a glitch in the reassembly process. Last night I hooked up my new DCC controller to the small layout, and began reprogramming and running trains- I found a glitch. One of my locomotives, a venerable old Atlas Classic GP-7, was making a painful whining sound! I recall it had begun last month after a decoder install and I shelved it. “Not tonight” I thought… I wasn’t going to let that nearly-new little loco continue acting up. Fixin’ time!
Upon disassembly, I found that everything was spinning freely and in its place. There were no rubbing parts or otherwise. I had to disassemble and reassemble the locomotive four times (decoder included) before I figured it out! It was the darn bearing blocks. Four little squares of plastic that have internal “fingers” that, when installed vertically, are held against the shaft of the worm gear and create a low-friction/ low-movement environment. Without installing the bearing blocks vertically (smooth sides of each block facing you when installed in the half-frame), these little puppies will make an awful racket that will drive your basic instincts to grab a hammer! Don’t smash. Just fix. I’m of the belief that this may apply to several locomotive manufacturers, including Spectrum and Kato, judging by the bearing blocks I’ve seen in those locos!
Summation- careful reassembly is apperently more important than careful disassembly, and just because it fits doesn’t mean it goes that way! [:-^]
