Triang X3121 (power bogie)

[Viscount]

I have one of these from the 60s and it has seen a lot of action over the years. Now trying to get it running again in the old Triang DMU.The issue I now have is that the bogie is fine when powered by wires to the wheels but when on the track, it rocks from side to side; one way powering forward and the other way powering in reverse. This causes a stall as the armature seems to jam. There is noticeable wear to the brass cog on the wheel sets in that they are concave. I have the same bogie type in my Blue Pullman which seems fine but the cog is better in that one.

Has anyone experienced similar and am I right that it is the cog and thus I need a new cog or wheel set?

[Mountain Goat]

It could be that there is wear in the motor bearings which give excessive play.
I am wondering if a more modern power bogie could be used instead? Those old Triang motor bogies do last a long time but even they wear eventually.
I like those DMU's though. Nice things.

[Viscount]

Thanks MG,

The bearings seem fine but I think I've tracked the issue down. I have a good one as well and so I swapped the wheel sets over and the fault stays with the chassis so I conclude it is not the wheel set. What I do see is that the actual frame is worn where the axles bear. It is more pronounced on the side that gets the load when going forwards. These old units have metal axles whereas the later design (like the Hymek) have nylon and that is likely why. I used to run my old one for hours as a child hence the likely reason for the wear. I've just won one on eBay; I was a bit doubtful initially as it is not clear if the wheel sets were of the lower profile to allow code 100 running but now I know I've got good code 100 wheel sets, I'm more relaxed. Fingers crossed the one on its way to me will resolve the issue.

[Viscount]

Good news. The X3121 bogie arrived today and works really well. Wheel set were the lower profile. Great to see my very first "train" running again.

[Chops]