Monday, 10 July 2017

Finding Gremlins in Locomotives

Performing surgery on a locomotive is a daunting task. Taking the body shell off to poke around inside and find out where a peculiar noise is coming from can very quickly take on the mantra of 'here goes nothin'. But a weird noise that had developed inside my 82 class diesel that only occurred when the locomotive ran in one direction, finally got the better of me. When it came to removing the screws as the instructions stated, the two screws holding the plastic body shell to the locomotive frame were fused in place. I only just managed to remove the first screw, bringing with it a smear of plastic shell that was embedded into the tip of the thread. The second screw wouldn't budge, and I soon burred the head off the screw completely. The simple task had brought on an attack of The Gremlins. The only way to get the shell off would call for me to drill the screw head out.

Fortunately the hole will be concealed when the fuel tank is reattached.

The cleanly drilled hole above wasn't easy. It took a full afternoon of trying different size drill bits before I soon realised that even with the screw head gone, the body shell would not budge from above the point where the screw shaft was still holding it firmly in place. I then proceeded to use a 3 mm drill bit while working at a very slow pace to completely drill the long screw out. This was hold-your-breath stuff as there wasn't a lot of room for error.

As you can see, there isn't a lot of room to be drilling through the die-cast chassis.

The finished hole needed a good clean-up and so did the area around the brass flywheels.

The culprit was this long screw that was fused to the plastic body shell. It still wouldn't come out.

Even with the body shell removed, the tip of the long screw still wouldn't budge when using a pair of long nosed pliers. Either there was an extremely strong factory worker in China who assembled this model, or the screw thread into the plastic body shell was torn out during assembly and the screw was then glued into place. In the end I just snipped what remained of the screw as close as possible to the shell, and left it there.

The noise ended up being the masking tape around the wires. It dried out, came loose and was rubbing on the drive shaft.

I thoroughly cleaned the inside of the model, removing the green plastic circuit board and both blowing out any metal shavings and dabbing every nook and cranny with a cotton tip dipped in methylated spirits. There didn't seem to be anything amiss, or any reason for the strange noise apart from the paper masking tape that had been used around the wires leading to the locomotive cab. It had dried out, come loose and had possibly been rubbing on the drive shaft powering the worm that drives the nylon gears. Because of the angle the loose paper tape hung down, it was plausible that it would only make a loud noise when rubbing against the direction of the drive shaft, not with it. It would make sense as I only heard the noise when the locomotive travelled in one direction.

I also inspected the gears beneath the cover plate beneath the bogies, or trucks, and cleaned away some dried up lubricant.

I also removed the cover plate from the bogies, or trucks. Some of the excess lubricant inside had dried up to a goopy-green paste and collected around the axles. I wiped this away with a clean cotton tip and put the cover plate back on.

I taped the wires back up using blue electrical tape and then screwed the body back in place.

With the locomotive thoroughly cleaned, I placed it back on the track and it ran without any noise. One nuance with the model had always been the coloured wires leading to the locomotive cab that were visible through the windows of the driver's access doors. So I replaced the dried out paper tape with some blue electrical tape before screwing the body back in place with the one remaining good screw. The fuel tank clipped back into place and concealed the 3 mm hole I had drilled.

The re-taped blue wiring is less visible through the driver's door window than before.

Placing the locomotive back on the track, not only was the noise gone, but the driver's door window looked much better. If you can see a hint of wiring in the above picture, it at least matches the colour of the locomotive. One thing I will give this model, it is made of sturdy materials. Nothing broke or came loose during surgery which I suppose is a credit to On Track Models. However, the fused screw and shoddy paper masking tape inside, turned what should have been a 5 minute inspection into a trip to the dentist! I wonder how many other owners of this particular model have run into the same problem? However, given that this loco has now performed over 2 years of service on my layout, I'm just glad to have an old favourite sounding healthy again.

See also; Review: On Track's 82 Class

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Thanks for taking the time to visit Philden. I hope you'll book a return ticket soon. Cheers, Phil