Here are some clearer photos of the same trucks...(click on the photos for an enlarged view)
...the Bachmann tender trucks for both the Consolidations and 10-Wheelers (and perhaps other Bachmann HO tenders) seem to all have the three-spring set-up in the Andrews trucks...
...and also in the less commonly-seen Commonwealth-type trucks...
...while the only Athearn steamers I have are the USRA Mikados, I'd guess that the same trucks are used, at least, on their USRA Pacifics, too...
...and I was again surprised to see the same type of Andrews trucks under my much-modified Proto-2000 Heritage USRA 0-8-0...
In my opinion, your best chance of getting some would be from Bachmann or Athearn/Genesis, but you could also try contacting Walthers on the chance they have some of those Proto trucks.
Since all of the Andrews tender trucks have the 3-spring arrangement, I wouldn't be too surprised if they were all from the same source.
Wayne
If the not-too-clear first three photos are causing hesitation, I'll try to re-shoot them using a better camera...they're all very similar to those in the fourth photo.
Well, talk about being unobservant...I don't recall ever seeing trucks with triple leaf springs, but after reading your post, took a look in my supply of trucks for yet-to-be-built projects and found two pairs.One pair is brass, the other is in engineering plastic, likely Delrin.
The latter ones looked like they might be from a tender, but had fully insulated wheelsets.That prompted me to take a look at what was on my layout, and I found four Athearn Genesis Mikados with similar trucks, with the three spring-set-up....however, I had installed all-wheel pick-up on those tenders when they first went into service (they are the same trucks as the those plastic ones mentioned earlier). I then checked my Bachmann Consolidations, 10-Wheelers and a Mountain, and found similar three-spring trucks on all of them. They too have been modified for all-wheel pick-up.
I'd guess that you'd be able to find either types directly from Athearn/Genesis and/or Bachmann.
(I'll take a couple of photos, and post them here shortly.)
Here's a look at those on an Athearn Genesis Mikado...
...and under the tender of a Bachmann Consolidation...
...and a Bachmann 10-Wheeler...
...and the Bachmann USRA Light Mountain (a Mohawk on my layout)...
I've tried for ages to get more of those ones with the drop-equalisers, but to no avail.
I am trying to locate a pair of HO USRA tender trucks with triple leaf springs but cannot seem to find any via the usual sources like Walthers, Precision Scale, Kadee, etc.
All I can find are those visually similar listed as caboose trucks but with only two leaf springs. I did however find suitable ones at American Scale Models -- and real beauties at that complete with scale chains attached to sideframes -- but they are $40 a pair...a little too rich for my blood.
I'm really surprised at the apparent scarcity because obviously there were a heck of a lot of USRA switchers in service all over the country early in the 20th century.
What am I missing?
Thanks,
Ed