Replacing blind drivers

There was originally a phosphor bronze finger spring in there.  You might try MTH parts?

bob2 posted:

There was originally a phosphor bronze finger spring in there.  You might try MTH parts?

Really!? I've never seen any springs on the axles of MTH engines. At least not on the diesels I have. 

I think you're talking about the two innermost axles of a six axle diesel.  The tighter the curves the more the trucks hang out.  There was a "how-to" article I saw somewhere about replacing the blind wheelsets with flanged wheels.  I think the writer of the article pressed NWSL 33" wheels onto an axle inside a Plasticstruct piece of tubing, but I don't remember how he fastened it to the truck.  Maybe one of our readers can locate the article.

See those two shiny strips in there?  This is a stock MTH unit.  Only change has been new wipers, but they look like the originals.  I did not add the finger springs.

I note that this is a factory 2-rail unit.  Could be the 3 rail units did not need springs.

I think I wrote an article about converting Scale Craft uninsulated wheelsets using insulated bolsters and Plastruct tube, maybe a quarter century ago.  Not sure which mag; at the time I was writing for OGR and OSN (with concurrence from both editors).

Bob2:  I don't think this is the article I referenced.  The article dealt with MTH trucks.  It was only in the last year or so.  The reason I remember it was because I asked my local repair guru if he knew of any remedies for the very same problem.  This is one of the signs of old age: memory loss.  

The three-rail units were designed to negotiate O-31 curves (15.5" radius)--O-42 (21" radius) on the longer diesels. They had a bevel cut on the inboard wheel sides to allow the wheel to drop on the outside rail and ride back up onto the rail on straight track. There were no springs as this would fight re-railing. If you wanted to flange that axle, you'd restrict the curves to something around O-54 minimum (27" radius) or larger off the top of my head. You'd also need to fix them in place or add stiff springs to prevent climbing/derailing in curves.

bob2 posted:

I note that this is a factory 2-rail unit.  Could be the 3 rail units did not need springs.

Ah yes, that's the difference here.  Mine is a factory 3-rail version. On the 3-rail truck block, the uppermost (in your picture) axle doesn't have those spring and the axle just floats freely. 

AGHRMatt posted:

If you wanted to flange that axle, you'd restrict the curves to something around O-54 minimum (27" radius) or larger off the top of my head. You'd also need to fix them in place or add stiff springs to prevent climbing/derailing in curves.

I'm not concerned with the larger radius, the minimum radius I have is O-72.  The spring (and maybe a spacer) is exactly what I was wondering about though.