I recently purchased my own Brass engine for my layout. It is an HO Scale Brass Canadian National K5a Hudson model from Samhongsa. For some reason it’s front trucks began to suffer from details when it starts going around a curve. Mainly it happens when the model goes around my oval track in clockwise direction. I did some observation and found that the front driver wheels seems to wobble; the front drivers might be getting picked up by that wheel, and that could be the cause of it derailing, even on 26" curves.
It’s my first time servicng a brass engine in over five years. The wheels are in their normal three o’clock position, and no gears or piston rods are getting locked up as far as I can tell. Just that it needs some quick lubricating and the wheels to be cleaned. How would you go about fixing a wobby front driver wheel? And have you had an issue similar to this that could be useful?
Any help would be very useful.
I’m ASSuming that the first-driver-pair ‘wobble’ is free lateral play. For the problem to occur only ‘one way’ on curves suggests that shimming on the side to which the drivers are being forced would be an option.
But that shouldn’t be derailing the pilot truck even if the driver flanges are lifting the chassis on one side. Most model lead trucks don’t work like the prototype: they are freely suspended and pivoted, so their four wheels can accommodate to the line and surface and ‘track’ properly.
Be sure the truck pivot has enough clearance that the truck can twist a little and keep all four wheels on the track. Then look at the arrangement used to keep the front truck frame ‘down’. That might be helped by added weight on the truck frame or even wrapped around the axles, or by a soft spring around the pivot pin that keeps the frame held down but free to pivot and twist to follow the track.
Test the engine on the track with the front truck/bogie completely removed to see if the driver lateral is causing a guiding problem.
Here is a Google Drive link to a slow motion video of the derailment happening in action. This is the first time a derailment is happening like that; it can’t be the track since none ofnmy other similar steam models has that kind of issue.
So the front part of the front bogey jumps off first, than the rest follows after. Another issue is that this derailment doesn’t happen on some occasion. I say 65/35 the derailment happens.
I did it. I think i found the issue. The spring wasn’t strong enough to hold down the bogey. So i simply added four washers underneath it and now it seems to be working as intended.
For now at least.
I’ll run a few more tests to make sure its all dandy.
